The first step to learning any app is to get acquainted with the nomenclature. This is what things are called. In OnSong, there are books and sets which are used for different purposes.
You can think of books as being different ways to organize all the songs in your library. You might have a book of 10 songs from the same music album, and you can call that book the title of that album. Books are great for organizing by topic, genre, band, album, etc. You can learn more about books in our tutorial video, or learn more about this feature in the user manual.
On the other hand, sets are used to organize songs when you are performing a gig or a show. You can put together a set to hold songs from multiple different books, depending on what songs you want in that set. You can learn more about sets in the tutorial video or learn about the feature in the user manual.