How can I create/change models/skins for REPO?

Hello everyone, I never modded a game before, but Im trying to make skins for REPO using Blender, but I cant find the models of REPO anywhere in the folders. I extracted them using dotpeek and placed it into VSCode, anyone knows how to help me?

I also tried looking for a bunch of tutorials, but I only found out how to get to the code archives, not the model ones (at least, I couldnt reach REPO ones).

Thanks in advance