Newb.. help pls

How can I duplicate a button and it’s function.
i.e. a help button that shows up on multiple pages/movies - but always takes the user to the same place.
I’ve tried to copy paste but then the function is lost. I’ve duplicated and renamed the movies, copied my action script and inserted the new name — and still the function is lost.
Sorry for the stupid question. But any help would be great.
David