I would say, start with getting a "simple" idea, like, adding a piece of clothing.
Find a mod which does something similar, and try to copy that mod and modify it, or dissect that mod until you got something working :-) (Eg: find out what makes the mod "work" and clone that behavior to accomplish your goals)
Find a mod which does something similar, and try to copy that mod and modify it, or dissect that mod until you got something working :-) (Eg: find out what makes the mod "work" and clone that behavior to accomplish your goals)