Guide on adding a new model, animation, and creature to HoMMV

Initially, the plan was to create a mod for Heroes 5, but based on a DIFFERENT game – from the Total War series, for example, Attila....
The reason is the performance issues of Heroes on incredibly large maps, and the resulting impossibility of comfortable gameplay,
plus, I want a new perspective on old acquaintances – Heroes 5 is my favorite part... and I would like to play with my favorite characters in real time (battle in Total War is not turn-based)....
But if we are going to do it properly, and transfer Heroes to Total War, we definitely need new animations,... because in Heroes, there are only 9 animations for a Titan, I counted yesterday.... But for this game, that's more than enough in principle....