Using the Media Browser, you can find and import songs from your iTunes library and movies from your Movies folder into a GarageBand project. You can also import GarageBand projects into the current project.
View buttons: Switch between Audio and Movies view.
Audio tab: Shows the audio files in your iTunes library and Music folder.
Movies tab: Shows the movie files in your Movies folder and iPhoto library. If you have Final Cut Pro X installed on your computer, your Final Cut Pro projects also appear in the Movies tab.
Results list: Displays the media files in the selected location.
Play button: Click to play the selected media file, or stop playback if the file is playing.
Search field: Enter text to search for media files by name.
Click the Media Browser button 
in the control bar.
Choose View > Show Media Browser (or press F).
For more information about using the Media Browser, see Use the Media Browser.