Background music in this tutorial includes:
- The Back Rhode Home
- Groove On
- Miller's Theory

Here's what the video says if you can't get it to play:

1. Go to the (your) project, the one you want to publish
2. Click the Info & Settings tab
3. Click Publish

If you can't get it to play, close your browser and open again. This video is very informative specially to those who wish to understand about licensing and revenue.