Start your Mac and open GarageBand. For this example we will CREATE A NEW MUSIC PROJECT. If you really don't want to make any decisions you can use MAGIC GARAGEBAND, which will open a selection of GENRES. Simply select a GENRE and then use the AUDITION button to modify each instrument. This is easier, but does not provide the flexibility that you have when you create our project from scratch.
When you open a new project the timeline will be empty. In this case we have already added some loops to the timeline. To select the loops, click on the EYE button and then choose the instrument to display the loops for that instrument on the right. You can also select an instrument and write for that instrument using music notation. You can then record your composition and add it to the timeline. Although I can read music, I can't write songs, so I stick with the loops.
Scroll through the loops until you find one you like. Click on the loop to preview it and click on the space bar to stop the preview. Notice the counter which shows you where you are located within the song, the tempo and total measures. To add the loop to the timeline, simply select the loop and drag it to where you want it within the timeline.
Once you have added the loop, you can adjust the volume using the volume slider. You can also adjust the pan of the loop allowing you to create stereo effects. Try using the same loop twice and panning first to the left and on the second loop to the right. This will cause the sound to move from one side to another
When you have the song the way you want it, double-check the time you need for the soundtrack in your iMovie. Make sure the song is exactly the length you need for the movie you are creating, then click SHARE from the top menu and choose EXPORT SONG TO DISK. Notice you can also export the song to ITUNES or burn it to a CD.
Integrate the saved song into iMovie. To do this, first open iMovie and find where you need to insert the song into the movie timeline. Then open the iTunes browser to find your song and drag it into the appropriate spot on the movie. It will appear as a green bar or "voiceover" below the video. Simply click on the SPEAKER icon to adjust the volume of the track and the ducking. Ducking is the volume of the other soundtracks in relation to the voiceover track that you added. You can make the volume on the song low and have it below the synch sound track or eliminate the synch sound and just have the music. It is that easy!