When adding a new file or folder in the CMS, your navigation items may shift in order within in the navigation menu on the website. The fix is relatively simple.
1) In the folder listing on the left, select your folder by clicking the little arrow next to your folder name.
2) In the file listing on the right, Click Order in the column to sort the files and folders by their index order.
3) Drag the files in the order you want them to appear in the navigation. #1 should always be your index page.
4) Publish the entire folder to update the navigation on all pages.