I finally managed to put the standard third-person character controller into another human model. I want to put the youtube tutorials I used here so I can remember how to do it again later.

This is a start, but I messed up somehow
https://www.youtube.com/watch?v=i7a_wlAKB7I

Finished it off with this.
https://www.youtube.com/watch?v=LOMiKKO9VSc