How to Create a Project in iMovie
When you have finished video, you’re ready to create an Apple iMovie project. You can combine all those segments from an event, taken at various times during the day, into one project so that you can edit the raw footage into an actual movie.
To create a project in iMovie, choose File→New Project and name your movie something that indicates its content. If you’re using video contained in one or more events in your project (and you probably are), just select the source video clip and click the Add to Project toolbar button. Alternatively, drag video to the area where you want it to show up in the project.
Then choose an aspect ratio, movie jargon for the way the screen looks. Your choices are
Standard (4:3): If you choose this setting and watch your video on a modern widescreen high-definition television, you’ll see a black space on each side of the video, otherwise known as a pillar box.
iPhone (3:2): Go with this setting if you plan to watch the finished movie on Apple’s smartphone or the iPod Touch.
Widescreen (16:9): This is the theatrical HDTV aspect ratio. If you watch 16:9 video on a standard TV, black spaces will appear above and below the video to form what is known as a letterbox.