Sharing your video with iMovie is a simple process.
iMovie 9 and earlier:
1) Select Edit mode
2) Choose the Group in your Library that contains the video
3) Under the Videos section, highlight your video
4) Under the Share section, select iMovie
5) Your video will be encoded, and then sent to your iMovie library
iMovie 10:
1) Select Edit mode
2) Choose the Group in your Library that contains the video
3) Under the Videos section, highlight your video
4) Under the Share section, select Movies
5) Your video will be encoded, and then sent to your Movies folder
6) Manually add your video from your Movies folder, to your iMovie Project
iMovie 9 and earlier:
1) Select Edit mode
2) Choose the Group in your Library that contains the video
3) Under the Videos section, highlight your video
4) Under the Share section, select iMovie
5) Your video will be encoded, and then sent to your iMovie library
iMovie 10:
1) Select Edit mode
2) Choose the Group in your Library that contains the video
3) Under the Videos section, highlight your video
4) Under the Share section, select Movies
5) Your video will be encoded, and then sent to your Movies folder
6) Manually add your video from your Movies folder, to your iMovie Project