Getting a new film listed (all credits...from scratch). How do I do that?????

I'm an actor.  Did a film 2 1/2 years ago.  The Producer assigned other people to get the credits listed and they have not done so, so I'm taking things over.  How do I...1.) get the film listed in the first place?  (It premiered in August of 2021.)  I think I can figure it out from there.  Thanks for all your help in advance.