want to make mongols playable but without hotseat

i want to be able to play as the mongols/timurids, but i dont want to do it the multiplayer way as i want to play from the very start and i want to be able to fight my own battles.

i downloaded a mod that does this and attempted to copy what had been changed but whenever i choose to play as mongols it reverts back to the single player screen

the reason i'm not using that particular mod is because of all the other changes it makes to the game.

i do have a little modding experience, but it seems it's more than just adding mongols as playable faction, adding units, and adding victory conditions.

thanks