Introducing myself, and giving some answers to questions I am frequently asked
Using iMovie on a Mac
Apple Mac computers come loaded with iMovie, a movie editing program that's very popular. Here are three short videos created by young people (in the first case, what sounds like a child of about 12!) that can show you how to use it if you are new to video editing. Take a look at these and try out video editing--keeping in mind that what you are doing for your first project is really just assembling still images, each of which will appear as a "clip" for about 5 seconds.
Basic iMovie editing starting from scratch (by a really young person!)
Deeper into iMovie, making an intro, also by a fairly young guy
5 advanced iMovie techniques by a fellow who looks a bit more mature