iMovie: Interface Overview

1. Menu Bar: Access general program operations such as New Movie, Preferences, and Help.
2. Project Bar: Switch between created projects, show/hide media library, and import media.

3. Browser Tabs: Changes the accessible assets and media in the Browser. Imported media is located in the My Media tab. The different tabs will change the interface.

4. Browser: Imported media, organized by the selected Library and Event, are stored here. Other assets, such as Titles, Backgrounds, and Transitions, are also accessible here.

5. Library Panel: Libraries and Events are stored here. 

6. Adjustments: Enhance the movie here with adjustments such as color balance, crop, and speed.

7. Viewer: View imported media and the movie in the Timeline.

8. Timeline: Build your project here. Split, modify, and arrange clips; add text and transitions.

To zoom in and out of the Timeline, use the slider located to the top-right of the Timeline. Click-and-drag the slider left to zoom out, and right to zoom in.