The easiest way to control page numbering for the entire book is through the Manage Ladder menu.

Access Settings: In the Manage tab, click Manage Ladder. 

Click the # Page Numbering button at the top toolbar
 

Toggle Off: There will be a checkbox or a toggle switch to. Toggle this setting Off to hide page numbers throughout the entire book by default. This automatically turns the page numbering off without hitting the Save Settings button.
 

This automatically turns the page numbering off without hitting the Save Settings button.

After making any changes to page numbering, it is highly recommended to check your pages in the Ladder view or use the Preview Book Tool to ensure the numbers are hidden.