While in the library view, there are 3 important buttons:
Settings – Toggles for device activation and 3g/4g warnings
Get Books - Download books from your archive
Edit - Delete books from your library
Reading View Menu
Tapping the menu button while in reading mode will give the options to add bookmarks as well as guided zooming/font settings. To access the other features, tap the center of the screen to open the nav bars.