Step 1: Go to the Read screen Tap on the "Tools" button at the top. Tap on the GRAY CHECK MARK.
Note: if you don't see a gray check mark after tapping on "Tools", then your device is already registered.
Step 2: Under "Mantis User Info", tap on "Enter username"
Step 3: Tap in the "mantisbible.com username" field
Step 4: Type your MantisBible.com username and password
Click Done, and then Done again. Now, when you re-start the program, any new purchases will show up in red.