1. Locate the desired page and click on the Edit tab.
2. Scroll down and click on Book Outline.

a. Book: Select the book that this page should be a part of from the drop-down menu. Or, if this page will start a new book, click <create a new book>.
b. Parent: If this page isn't the top-level page in new book, a drop-down menu will appear here. Select a Parent item from the list. This is the page that the new page should appear under.
c. Weight: (Optional) Pages with the same weight will appear alphabetically in the book. Pages weighing less (a negative number) will float to the top of the book. Pages weighing more (a positive number) will sink to the bottom of the book.
3. Save the page.