So I'm making a mod. I need one of the characters to do the "special" dance. But I dont know how to add the animation file. I know it's "anim_dancingGirl.NIF" because I looked at Caminda's file, but I dont know how to add the animation to a new character. Help?

There should be an animation button on the NPC tab. Just add that file and your NPC should be able to dance whenever idle9 (I think) is called.