OK, this image shows our Manage Pages display. See that, though I do have some child pages created, there are red numbers only beside the four parent pages. Those are the ones that will show in the top bar. I took a screen shot out of the home page of the top bar buttons and inset it here. See that the buttons have the corresponding red number above them. This theme numbers from right to left, unlike most, so the first page is on the right.
Another inset shows the arrow and large text "About page." This inset is taken from the bottom of the screen where the page is created and set up. There is this page order box at the bottom. All we have to do is place the number for the order in that box and save the page. So, when we built each of these parent pages, we went to the bottom of the "Write Page" screen and entered a number from 1 to 4. It could as easily have been 1, 3, 5 & 7, as the order will be numerical. Actually, it could be a good idea to skip a number early on, as you may want to insert another parent page later, and you won't have to renumber.