Order of HTML U2

On the left of the screen, my students want to order the .html (they are calling them tabs or new pages) tags in a specific order. How can they rearrange the order?

The HTML pages will rearrange in alphabetical order. If they are clever with their terms, they can get it in the order they want. If the put a letter in front of the name, they can easily rearrange the order. They will not be able to rename the “index.html” page.