How do I navigate through book pages?

Navigating through a book structure/between book pages is relatively simple once you know how:

 

Book menu nav 1
 
Within the main part of the page, you can use the 3 options at the bottom of the book page, which link to the 'previous' and 'next' pages, and also move 'up' in the structure to the 'parent' of the page that you are viewing (if there is one).
 
Book nav 2