Open iMovie on your Mac.
Connect a camcorder or other video recording device to your computer. If importing high-definition (HD) video, choose which resolution you want for the video (full-size or large) if asked. A window may automatically open, showing you thumbnail images of all the video clips on your recording device. To import all the videos, click the "Import All" button. For importing selected clips, move a slider control in the bottom left corner of the window from "Automatic" to "Manual." Uncheck the boxes by clips you do not want to import to iMovie. Click the "Import Checked" button. Choose where to save your video clips, such as on your computer's hard drive or an external drive. Give a name for your clips, which will be saved under a new or existing "Event." Decide if you want iMovie to import video with "Stabilization" to help improve any shaky video and/or identify people in your video. This can considerably lengthen the importing process and is an optional choice that can be done later. Click "Import" when ready to add your video clips to iMovie. Find your imported video under its saved name in the "Event Library" in iMovie.