Building on an existing Movie Clip

How do I add more images to an existing movie? I did not create the 5-image movie and want to ‘add’ to it. The 5-images plays in a sequential movement ending with the first image. I want to add more images within the movie, but do not know how to do this. I only know how to swap out images.

I tried to duplicate the Movie Clip, but that didn’t work.

Let me know if you need to see any coding from the existing Flash file.

Any helps, would be appreciated.