How do i mod parasyte in city?

[Casual modder]

I want to do at least one, but ideally more than one or all, of the following modifications:

 

1. to add another playable character... or at least to modify the appearence of the character (that way i just have to have the original copy and the mod if i want to play a character or the other)

 

2. Add new enemies (in other words, new ways of getting the protagonist raped)

 

3. Add the possibility of triple rape( there is already the possibility of two enemies raping you, but there are three holes so...)

 

4. Add a fourth stage

 

Ideally i would like to do all, but just doing one of these would be nice. specially #1 or #2

 

note: i am a newbie at modding