You can change the order that your pages are displayed when using a default menu by using the Order field of the Page Attributes module.
Let’s say you have three pages: About, Photos, Contact
If you wanted About to appear first, you’d need to do the following:
- Go to Site → Pages in your dashboard
- Find the page About and click the title.
- Locate the Page Attributes module to the right of the editor.
- Put the number 1 in the box for Order. This tells WordPress to display this page first on your site.
- Click the Update button.
Repeat the process for your other pages, but use higher numbers for the Order field: 2, 3, etc. This tells WordPress to display these pages second and third on your blog.