Looking for a guide or tutorial

I am trying to build my own little top-down click dungeon crawler hack n slash game. I have had no problem doing that so far but I want to be able to choose / customize my character.

Like changing the face / body and picking clothes and items. I have no idea where to start. If anyone can maybe give me an indication of where to start or what to think about that would be great. I tried looking around but couldn’t really find what I was looking for.