
Generally you should create a new library for your project, as otherwise you may eventually have several project’s media in your main iMovie Library.
Timeline. The bottom is your timeline of edited media you can trim video clips in the timeline as well as adjust audio. The media viewer has a number of color- and audio-correction options above it, so you can perform adjustments to color, crop an image, apply a Ken Burns effect on a media clip, and a number of other helpful editing options. On the right side is a media viewing area of either the media in your timeline, or media you have selected in your project media area. You can also find titles, backgrounds, and transitions in this area. iMovie arranges media into libraries, which you can find here. This will include your collection of media that you may have imported, as well as quick views into your iPhoto library, and any music from your iTunes library and GarageBand. Project Media. On the left side of your screen is the media for your project. In this project view, iMovie is broken up into 3 distinct areas. iMovie will then bring you into the project view for your new project. If you haven’t created a project, create one by choosing File/New Movie. Generally, iMovie opens your last edited project. Theater: View movies you have exported/shared, or create a new movie or trailer here as well. When you create a new project, you’ll be prompted to choose either a Movie or Trailer project choose Movie. Sometimes it’s useful to duplicate a project here if you’re doing a different edit on a project. Projects: A collection of your edited projects. Media: Where you store your content may have different libraries that contain different media.
IMovie is organized into 3 thematic areas, generally found at the top of the screen unless you have already opened up a project: Here’s a brief video that covers how to start a project, import footage, do a quick trim, then export the movie.
Note: There is a list of iMovie tutorials online at the bottom of this page that are extremely helpful.