Apple's iMovie software provides tools to import video and edit a series of clips to create your own custom movie. The import options let you add video from files on your computer, a tape-based or digital camcorder, HD video, DSLR cameras, the iPhone and other iMovie projects. iMovie lets you arrange clips in the sequence you prefer, add effects and audio to each clip, crop out portions of video you don't want and apply overall effects to the movie.
Open the "File" menu and move the mouse over the "Import" option. Select the video source you want to import. For example, to import files on your computer, click the "Movies" option. Skip this step if you already have content in iMovie.
Drag the video clips down into the "Timeline" section of the iMovie interface. This is the bottom section of the window. You can toggle between timeline and clips view.
Click and drag the clips in the timeline to arrange them in the order you would like them to play. Click a video clip to select it. Click the points in the "Playhead" above the timeline to select your stop and end points.
Open the "Edit" menu and click "Crop" after selecting the start and end points for the clip. Repeat for each clip. Click the "Editing" button to add effects to your clips.
Click the buttons to add text, transitions and audio effects to each clip and the movie. Set the "Effect-in" and "Effect-out" times to "0" to set an effect or audio sequence to play for the movie. Use the "Export" or "iDVD" options in the "Share" menu to export your video to other formats.
Save regularly to avoid any issues.