Custom Playable Characters?

[NegativeInfinity]

Hello. I feel like this is gonna a blatantly obvious question that will make me seem ignorant, but how would one go about making a playable character like as in the player actually controls the thing? Also, like in GvH, I would also want different characters to have different weapons and stats etc.

[Ænima]

http://zdoom.org/wiki/Creating_new_player_classes