This setting controls the order of pages in the “Pages-> All Pages” dashboard interface, and the order of menu links in pages widgets. Page order can be set in both the quick edit interface and the full page editing interface. We recommend the quick edit interface if you’re setting the order for multiple pages.
When a page is created, it has an order of 0. Pages are sorted from lowest to highest, so 0s will be listed first. Unfortunately, since all pages start at 0, you will need to assign all of your top level pages an order to make full use of this feature.
Leave room to grow!
Chances are you’ll need to add more pages later, so we recommend numbering your pages in increments of 10 (10, 20, 30…) so you can insert pages between existing pages without having to renumber all of them.
Child pages are only compared in page order to its siblings (other pages with the same parent page). There’s no need to try to make child page orders fall between parent page orders- you can start over at 0.