The iMovie timeline is where you edit your movie by adding, arranging, and trimming your video clips.
Pinch closed in the center of the viewer or the timeline to zoom out, or pinch open to zoom in.
Zooming in lets you see more detail in each clip in the timeline and may make it easier to trim clips. Zooming out lets you see more clips in the timeline at once, without scrolling.
Zooming in and out doesn’t affect the duration of your clips or your movie.
Move the playhead to the beginning of your project: Touch and hold the left side of the timeline, where the video meets the edge of your screen.
Move the playhead to the end of your project: Touch and hold the right side of the timeline, where the video meets the edge of your screen.
Note: You can use an Apple Wireless Keyboard to quickly navigate within your project. See Keyboard shortcuts.