OnSong is designed to store your entire OnSong library on one device. This means that if you want to use your current library with another device, you will first need to transfer it to the other device. This is accomplished by backing up your library on your first device and restoring your library on the second device, which only takes a minute or so.
Here's a video tutorial that shows you how to do this using Dropbox:
You can also transfer your library using iTunes instead if you do not have Dropbox or an Internet connection:
We cover more details on automatically backing up and restoring your library in our backup tutorial video here: