The Notebook holds all of your Notes, Followed Highlights and My Highlights.
To add a note, tap and hold your finger on a word. Then tap “Add Note” from the pop-up. Enter your text and tap “Save.”
To create a highlight, tap and hold your finger on a word. Drag the end point to select all the text that you want to highlight. Then tap “Create Highlight” on the pop-up.
To access your notes and highlights later, tap the Notebook icon.