You will direct a song that will have four of the following and you will video tape each as they do it using one cut with good composition, lighting, and angles:
Record
GarageBand Edit
Export the other three audio from the videos using iMovie > Quicktime > AIFF like you did for the main musician. Import into GarageBand so that you have all four tracks. Now you will edit what you need to in order to make each the appropriate volume and sound. Export the music out as the final edited MP3 file.
iMovie Edit
To create four separate video screens in one video, watch this video tutorial. After you have imported and synced all four videos then import the final edited MP3 file from the previous direction and sync it with the videos. Then mute the other video audio while keeping the audio for the edited MP3 file. Export the final video to your desktop and a copy to your dropbox as a backup.
Post
When finished, post to your vimeo account and the link to your Posterous and to the task spreadsheet.