I've heard that you can hide a staff from view (like in the sample Moonlite--I heard that the trill was just inserted text and the actual trill was played on a hidden staff). How do I do this?
On the menu bar, choose "File", "Page Setup", Contents (tab) and click off the box of the staffs you desire to hide.
If you have one or more hidden staves that you don't want displayed when someone uses NoteWorthy Player, you have to put them into a group named "Hidden". Putting staves in groups also makes it easy to hide/unhide the entire group with one click in the Staff Properties window as described above.