Concept of Character Creator


I am pretty experienced with the blueprints in Unreal Engine, and I wanted to make sometime an in-game character creator, just like in an RPG or a Sim game like the Sims, to advance my level even further. But I am not familiar with the concept of character creators, so I would like some help on how a character creator works, and a general overview on how it could be made in blueprints. I would be happy if you could answer.