All files are packed as bsa. To unpack these files you need BAE: https://www.nexusmods.com/skyrimspecialedition/mods/974/

Objects are stored as nif files and contain primarely three things.

1) Object shape

2) UV-map (with texture location)

3) Collision data

A more detailed explanation can be found at:

https://www.loverslab.com/blogs/entry/20368-skyrim-creation-kit-making-an-object/

Textures contain the visual image that objects will have when they are inside your game. They can easily be edited with the tool paint.net: https://www.getpaint.net/

Most textures are dds files however there are alos a few others. dds files only work when they are squares with a size that is a square number of 4x4 such as 256x256 and 1024x1024. Textures in skyrim can contain multiple layers of dds files (9 possible slots) in order to achieve the desired look. The path for these textures can be changed in nifskope or in bodyslide outfit studio. Keep in mind that the game can only display textures that are in the textures map (inside the skyrim data folder). If the textures are stored anywhere else, or are missing then the item will appear purple colored in the game. Not all items have 9 layers of texture. Most objects have only one to four textures applied. The diffuse path is for the main texture. Normal maps (usually displayed as _n.dds files are used to create the illusion of depth in an object. This way objects can appear to have a little crack in it without actually having a crack in it, reducing the weight and size of the object.

Lights in skyrim play an important role as they are responsible for a lot of the cell design. Light sources in skyrim are either spheres or cones. There are no other shapes of light inside skyrim. These lights can't move light through solid objects however their collision still does. If too many lights collide (by collision, not the light itself) this will result in flickering light on the place or a black spot. This black spot will look like a bug and won't be able to iluminate since the issue is too many light sources. Black spots can also be created by the player when running around with a torch. This is yet another light source that can overload the systems and creat a black spot. The framework limitation regarding these light sources is the main reason why everything in skyrim is either flat or has only two floors. Should there be more than two floors this will result in many issues regarding the lighting of the cell. Pressing the M key will show/hide the lights. If you press the A key you can quickly switch between full light or light source. The light source radius can be seen when you press the L key. I don't think you can revert light edits with Ctrl+Z. That being said, select object, hold S key, click and hold object, now drag, to scale the sphere. If you hold Ctrl+Alt+S, you will scale the intensity instead of the size. Lights with a purple cross indicate lights that cast shadows. These lights are heavier for the engine and should be used with caution. Generaly you should max use one light source that casts shadows in each room and then fill with no shadow lights.You can add multiple shadow casting ligths but then make sure they don't collide (maybe make the spheres small).

Navmesh in skyrim and the open world contains the data for npc's on where they can and where they can't walk. These places are shown as a red surface on the ground when you press ctrl+e in the creation kit. Existing Navmeshes can be auto generated in a cell but have to be manually tweaked most of the time. After editing navmesh the editor must finalize to make the changes permanent and let the navmesh adjust to the new situation. (new borders, doors,...).

Keep in mind that navmesh can only be used when it is connected and won't work when they are on 45° steep surfaces or more. (44° should still work). NavMesh can be activated by pressing ctrl+e. It will show all the red fields and give you a toolbar to modify. If you are editing a cell, placing navmesh should be your last step.

You can create square navmesh but the game prefers triangles. You can place new points on the map. Select three of them (existing or new ones) and press yellow/orange triangle to create a new one. Keep in mind that all the navmesh has to be conected in order to move along it. If Navmesh is too small npc's won't be able to use it. Every time npc's move to another triangle the game needs to recalculate. Try to cover big surfaces with few triangles and try to keep them evenly distributed. When you are finished editing you must press the ✓ key to finalize your navmesh. Upon saving it will turn teleportation navmesh green, edges yellow, and some edges that border with objects blue. This will all be done automatically you don't have to do anything yourself. If you don't finalize, your navmesh will not work properly. If navmesh covers surfaces with objects the npc's will think there is no object and run into it. For more options open the NAVMESH toolbar.

Collision boxes are yellow squares that show up in the creation kit. These boxes can be modified just like any other object in the game. Collision boxes are invisble bariers that prevent actors from moving through (actors are npc's, the player and objects defined as actor by script). Actors can however teleport through collision boxes on waiting or loading. Boxes can be made like shown in the image. Keep in mind that most objects already have their own collision in the nif files that is much closer to that of the base shape. (Meaning they don't need collision boxes.)

Trigger boxes are just like collision boxes but their purpose is the oposite. Unlike collision boxes they are meant to walk through by actors. You can apply a script to a trigger box like OnTriggerEnter or OnTriggerLeave. It is best to give your trigger box an unique name.

Event onTriggerEnter(objectReference triggerRef) 
	Debug.Notification("TargetRef "+triggerRef+" entered the box")
EndEvent

Event onTriggerLeave(objectReference triggerRef)
	Debug.Notification("TargetRef "+triggerRef+" left the box")
EndEvent

Scripts are where the mess begins. Everything in the game runs on scripts. These scripts are written in the computer language papyrus. Wiki quote; "Papyrus is an object-oriented scripting language developed by Bethesda Softworks for use in the Creation Engine. Papyrus first appeared in Elder Scrolls V". Every script in the game requires a trigger. Without trigger no script will run. These triggers can be attached, but are not limited to; a triggerbox, a quest, a global utility function, a dialogue line, an ai package, a spell, an object, an activate button, a mod menu, weather, animations, time, and an actor. These should cover most of the options to attach a script. Everything in skyrim that has a script box when editing that allows a script to be attached can become a trigger. Note; debug notifications are only for modding purposes. When showing message ingame making a message, defining the message in the script as a property, setting the property and .show() should be used instead. Example;

Event onTriggerEnter(objectReference triggerRef) 
	MyMessage.Show()
EndEvent

Message Property MyMessage Auto

Most of the time you need an event to start running a code. Events can be found here; https://ck.uesp.net/wiki/Category:Events

You can also find tons of scripts that are already written and fully working on this website. Feel free to browse around. Scripts are stored as pex and psc files. You can find the pex files under data in the sripts folder. For LE the psc files are located in the scripts, source folder. For SE the psc files creation kit uses are stored in the source, scripts folder. Pex files are the files that the game uses. Psc files can be edited in creation kit and read with notepad++. When psc are compiled they are turned into pex files for the game. Reverse process is not possible. Any attempt to turn a pex file into psc will result in a similar yet different file. If you remove scripts they won't be removed from your script folders, you have to do that part manually.

Quests are a major part of the game but are not always stable. Quest can start game enabled or they can become active during the gameplay by script. Quests can also be activated by following up on a previous quest. Quests can be set as main quest, misccellaneous, or a faction quest. Quests can be repeatable or only run once. It is important to remeber that the stages can only advance upwards. When trying to move to a lower stage from stage (50) the function MyQuest.Reset() has to be run first in order to run the function MyQuest.SetStage(30). This is due to framework limitations. Your quest will need an unique name, ideally you choose three or four characters that you put in front of everything and will only be used by you. This way you can filter and find your own edits very easy.

Quests can have as many stages as you want. They can be set in the tabs. Other tabs you might be using are Quest Objectives, Quest Aliasses, Dialogue views, Player Dialogue, Scenes and scripts. Under the Dialogue views quests can give acces to dialogue lines. Data of quests is stored and accesible at all time, regardless of where the player is. Explaining all the posibilties with quests is too much. I suggest you go through the toolbars and try some stuff yourself.

Dialogue is a part of the questlines. Dialogue lines can be added under the tab "Dialogue View" of a quest.

In order for the dialogue to show up in game, target conditions have to be met, the quest needs to be active (and if the quest starts game enabled a Seq file has to be generated with SSEDIT).

You can run scripts at the end and the beginning of the dialogue. In this given example at the end of the dialogue where the player says "I don't care" the quest will advance to stage 40. The quest will also have to be defined as property inside the script underneath the ;END FRAGMENT CODE. To run a script through a dialogue watch this video from Caden Black (10:20):https://www.youtube.com/watch?v=ivJuYlQ-d_Y

If you have FaceFXWrapper installed from: https://www.nexusmods.com/skyrimspecialedition/mods/20061?tab=files you will be able to double click the MaleOrc line in the white window and hear the sound from the voice file. If there is no sound that means that is either not working or you don't have a sound file. To make a sound file that plays with the text you need a .fuz file. Then make sure this .fuz file is installed at the location as given in the white window under path. Give the .fuz file the Voice Filename or in this case the name "DB13Everyt_DB13EverythingO_00019D16_1" in the folder "Data\Sound\Voice\Test.esp\MaleOrc". You can extract the .fuz files from vanilla skyrim and listen to all the lines with voice file reference tool: https://www.nexusmods.com/skyrimspecialedition/mods/18819

You can also just paste a .wav file in this folder with the Voice Filename. Once ck recogizes your wav file the Generate Lip File button will become available (this requires the FaceFXWrapper fix).

If you press the generate lip file button you will get a .lip file next to your .wav file in the map "Data\Sound\Voice\Test.esp\MaleOrc". If you put these two together in Yakitori Audio Converter: https://www.nexusmods.com/skyrim/mods/73100 you will get a .fuz file that contains both your .wav and your .lip file. Make sure you give this .fuz file the Voice Filename. If you don't have a fuz or wav file in the game, there will be no sound. Without lip file the sound will play but the actors lips won't move.

If you don't want to make a sound file yourself you can always use a limited amounth of shared responses that are already in the game under the "Shared Response Data From Info:".

NPC's (or non player characters) are part of the actor group. Npc's are just like real people, easy to make but less easy to work with. Just find an npc in the Object window drag it into a cell. Press edit, edit base. That will open up this menu. You have plenty of tabs such as traits, stats, factions, relationships, ai packages etc. Kind of self explaining.

Keep in mind that when you make an npc, unless they are CharGen Face Preset, they require FaceGen data or will appear in game with a black face. This is not a bug, this means your game is missing data. You can export the FaceGen data from your creation kit into you game folder by looking for the npc in your objec window select the npc in object window the press the keys Ctrl+F4. If this doesn't work try looking in your game. If you took a base npc and didn't modify the face you won't need to create FaceGen data. If you got a message, you will you find your facegen data at the location meshes\actors\character\facegendata\facegeom\"File".esp (for nif files) and texures\actors\character\facegendata\facetint\"File".esp (for texures). Make sure to include this in your mod or your characters will show up with black faces.

AI packages are actions npc's will perform when certain conditions have been met. Packages can be added to npc's directly but it is better (or so I have been told) to add them to aliases in a quest. Then force these aliases with their packages on the npc's with a script line Alias_SomeName.ForceRefTo(Npc). More information can be found at the page: https://ck.uesp.net/wiki/ForceRefTo_-_ReferenceAlias

Teleportation objects such as doors are very important in this game to move from Tamriel to a cell and back. All you have to do is place two doors. One in the outer world and one inside the cell. Right click on the object and in the object window you go to the teleport option. Make sure the doors reference each other. Once they are linked you can move back and forth by double clicking the yellow marker in ck. This will also allow you to use them in the game. For npc's to travel along, make sure you update your navmesh when a new door is installed.

Map markers are easy to create, altough they seem a bit bugged. I suggest you find yourself an existing marker somewhere. Copy this marker with the Ctrl+C and then paste it on the location that you want to become a new place. Go to the Marker Data field. Type the name of your new location and choose the type. Don't forget to place a XMarkerHeading. Link your MapMarker in the Linked Ref box by selecting the XmarkerHeading. When you fast travel to this map marker you will spawn at the XmarkerHeading in the direction that the XMarkerHeading is facing. That is all there is to it. MapMarkers can be shown/hidden with the M key together with the XMarkerHeading.

Music is an important part of the atmosphere. The music list to play in a certain cell can be found you press edit on the interior cell. In this list you can add as many tracks as you want.

Activate objects such as weapon plaques are fairly easy to make. All you need is a weapon plaque and a weapon trigger. Open the the weapon rack activator menu by clicking edit and connect the weapon rack in the Linked Ref tab. Make sure it has the keyword WRackTrigger. Open the reference menu from the weapon rack and add the weapon rack trigger Linked Ref with the keyword WRackActivator. It is the same for weapon plaques. Mannequins are a little different. Make sure you don't make weapon plaques with an angle of 90° they will be bugged. Mine are at 90.0208 degrees. If it all sounds a litte confusing you can use a tutorial on youtube like this one: https://www.youtube.com/watch?v=qGdfilJ12l0 or this one: https://www.youtube.com/watch?v=tcdA8sDZlD8

Crafting stations can be modified, however when you do edit the base objcet, the animations will no longer work. Upon activating the crafting stating will open the crafting menu but won't play an animation anymore. Some might find this sad others might find this handy. I don't know if there is a way to change the base object and keep the animations working. All you have to do to create your unique crafting station is make a new keyword for you station. Take an already existing crafting station. You don't have to keep the model but your station will keep the interaction box that the original model has. Small interation box for anvil, big ones (360°) for smelters. Press edit base. Make sure to give your crafting station a unique name (don't change the base object). You can edit the crafting station to look like anything you want. Remove (in this case) the CraftingSmithingForge keyword, this will disable all forge recipes. Add your own keyword instead. Now you can make crafting recipes for this workbench keyword. Only your recipes with that keyword will show up in your workbench You can also make more recipes for already existing workbenches. For ovens you have to remove the BYOHCraftingOven keyword. You can figure the others out for yourself ?.

Spells and enchantments (Magic) both need a magic effect attached to it in order to work. You can just mess around a bit with them. I personally don't like them. It seems like some of the data is embedded in the spells or enchantments that you are editing. Meaning you can't change certain things. Think very well about what kind of spell/enchantment you are going to use as the base of your new spell/enchantment. Unlike usual I think this choice does matter. You can see all three types in the image.

When you are editing your game, your changes will be stored in the esp. Scripts, meshes, textures, voice files, dialogue views and seq files are all standing on their own. If you save your esp files in another folder every now and then you can roll back when you break it. Make saves people, make saves!