Just click the Edit Page button on the bottom of the Soundtracks page. I recommend you select Correct/Delete so you can see how the existing tracks are formatted. Then when you're on the page with those tracks, find the drop-down to Add items, and add 1 item.
Based on what you listed above, it would look something like this:
"Concierto Para Mandolina in C Major" Written by [link=nm0006334]
If you have more info, like who performed it, you'll see other items with such info, and can imitate them.