Let me see if I can describe the process. First I use the DAW mode to put the individual tacks into Garageband. This gives me more control over the mix so I can set the volume of each track. I find it necessary to boost the gain on the bass solo over what BIAB itself does. When I record the video I'm listening to the playback of the backing tracks as I record my guitar and vocal, and I'm recording the guitar and vocal into the same Garageband project as I'm also recording the video. In my earlier attempts I used earbuds to listen, but I found this to be problematic for my vocal performance; I couldn't hear myself well enough singing and had some intonation problems with my vocal. But I found that simply listening to the backing tracks over my speakers solved this problem. Just turn off monitoring the actively recording tracks. And my microphones are cardioid patterned so they didn't seem to pick up too much of the playback to be a problem. My video camera is a Logitech c10 HD webcam that has its own microphone. I use Quicktime to capture the video. The draw back is Quicktime has a 720p limitation, but I have no alternative since the Logitech software doesn't work with Mavericks, and since the c10 is an old camera I know they will never upgrade the software. (With my previous computer running Lion I could get full 1080p video.) After importing the raw video into iMovie and editing the video with its beginning theme and ending graphics, I drag the completed Garageband sound file onto the video. The GB sound file then exists as an addition to the movie. You can see the wave forms of both the audio recorded from the camera, and that of the GB file. Then it's a matter of syncing up the two. This is a simple process of dragging the GB file to the left or right such that the wave forms look as though they match. Listen back. When the echo disappears (or becomes negligible) you've got it. Pull the volume line all the way down on the audio that is embedded in the video, which completely mutes it, and you are left with the Garageband audio file. Save and upload to Youtube. Hope that helps. Don't hesitate to ask if anything is unclear. Thanks for checking out my video.