TFS 1.X+ Where to start customizing TFS 1.6?

[Malvatroz]

Good evening everyone, I'm new to the area, I've always liked Tibia a lot and this year I finally managed to get a personal challenge underway, customizing a version of TFS to create a Narutibia, the version I chose was TFS 1.6, and I thought about starting the customization by adding a new vocation, with a custom sprite and everything, but I can't find anywhere where I can inform this sprite, I've already mapped all the places where vocations are passed and none of them have any information about the vocation sprite, so I was wondering, did I try to start this customization incorrectly? Maybe I have to start from the source? But where? If someone can clear up some of these doubts of mine I would be very grateful!