How to add a new page to the main menu on your website
Step 1. From the Dashboard menu, select Appearance then Menus.
Step 2. Select Main Navigation (Header Menu) under Select a menu to edit to add a page to the main navigation. Click the Select button.
Step 3. In the Pages module, you will see a list of pages that currently exist on the website. Check the box of the page you wish to add to the main navigation, and click Add to Menu.
Step 4. On the right side is a section labeled Menu Structure you will see the current navigation structure for the site. If the previous step was done correctly, the new page you just added will be located at the bottom.
Step 5. Click and drag the new page to its desired location in the navigation.
NOTE: All tabs that are left justified will be primary items in the navigation, and those indented to the right will be secondary in a drop-down menu. You can also add a page as a tertiary option if you choose to do so.
Step 6. Once the new page has been placed in its desired location in the navigation, click Save Menu.