Changing Page Order in Your Menu
You can Change Page Order (change the order that your navigation items display both at the top level and below) by first clicking on the Pages Tab and then clicking on "Change Sort Order."
Note that you control page order by the relative numbering of the pages. Your numbering does not have to be perfect. Just note that smaller numbered pages appear on top of larger numbered pages in the navigation system, for both top level and sub-pages.