outfit studio; how do i get the clothes to conform to my slider?

[megamanfan]

so, i copied one NIF file from the caliente folder to the same clothing's file in the meshes folder (trying to add physics to it, long story), but when i load the file from the meshes folder, it no longer conforms to the slider. please help.

[megamanfan]

and i just realised in-game that the clothes not only dont appear for some reason, but they also change my character's weight (she's supposed to be thicc)

[FauxFurry]

You need to expand the mesh of the clothing so that it covers the body for starters. Outfit studio is also not the correct tool to use if you want to customize the outfit to your character slider presets. You should be using BodySlide. 

It would help to watch a tutorial video on the topic so that you do not try to rush too deep into the process of converting outfits without knowing the basics.