log in to imovie theater with the apple store id but needed to log in with my separate iCloud id on the new Apple TV

in thew new Apple TV after downloading the iMovie theater app it had a log in with my apple iTunes account id, so I plug in the password, but after log in it couldn't download my iMovies in the iCloud . The reason I think it won't download is because my iCloud id is not the same as my iTunes id. but it never asked for my iCloud id & password. now I can't find away to log in to the iCloud account in iMovie theater, can't find a way to delete the app & start over. my previous Apple TV 3 had separate ids & you could go into settings to check them. how can I fix this problem ?