If you want to add Sub-Pages, for example a programs Tab. You would click on +Page, Enter the Title of the Main Tab which in this example would be “Programs."
This takes you to the quick edit form.
After clicking Save it will take you back to the Menu Editor Page. Looking at the Preview Page, you can see that there are two tabs. Named Program 1 and Program 2. We want to make these sub pages. In order to do this, Click on the Quick Edit Menu button.
Here you will see arrows on each of the pages.
When you click on the arrow, that page is immediately placed under the page above it. Now you have sub menus anytime you hover over the tab you want to access.
Repeat the editing process until you have the website structure the way you want it.