Verify your game files, make sure the mod is updated (steam can be funky, unsubscribing and resubbing can fix it), enable the mod in the mod manager of the warhammer launcher, make sure you don't have any conflicting mods turned on. That's it really, just pick an empire faction and good to go.

Edit: just realized the date of your post, you probably just had the temporary problem from the last total war patch, it broke every mod with capital letters in their units lol, should be fine now tho since they fixed it