The Library contains all the books you have downloaded to the Bible Study App on your iPad. To access the Library, tap anywhere on your screen to reveal the menu at the top and tap the Library icon.
Once you have the Library open, you can tap on a title to open it. If the title is greyed out, you still need to download it. There are also some options at the bottom of the Library that you can use to sort your books: View All, Recents, Favorites and Categories.