I've been learning to play the piano by myself for a couple of moths and today I came across a song in my book that got me confused. I know that double dots inside double bars means that you have to repeat that part, but what do you do when you also have lines and numbers above the staff? I get that they are supposed to mark two different verses but I literally have no idea what bits I am supposed to glue together. Could you please explain to me how to "read" them properly (probably there are pieces/songs where there are more than two numbers)? Also, what are they called?