Rome: Total War (2004) unit creation help (Total War: Rome)

Hello. Lately I’ve been shaman with old Rome, with troops, etc.) I want to add Culanna Dogs (From Barbarian Invasion) to the Dacians, I found a guide for adding a unit, it seems like I did everything, but in the end I messed up with something, and just when loading battles were thrown out ...
People who know how, please write down the full instructions on what and where to shove, and where to get)) Directly with the names of the files, so as not to do anything extra.
And after the question, mb who knows, also almost on this topic. In my data folder, there is neither a textures folder in unit models, for textures, xs where to find it, nor a UI folder to put an image for a new unit.
I hope there are old-timers left, who still gamble in such a rarity)))