The Notes tool allows you to make private notes on items that you view in the app. Here is how to use the tool.
Locate and open the piece on content that you would like to view.
Tap the screen to reveal the top and bottom menu bars (1). Tap the pencil icon in the top right of the screen (2).
The Annotations window will appear. Tap on the "+" to view or create a note
Tap the "+" to create a new note (1) and enter in the note (2). Tap 'ok' to save the note.
To delete a note, tap on the trash icon (1), and tap 'ok' to delete (2).