1. Go to your Apps > Navs
2. Select "Edit" to the navigation you want to make edits to.
3. Scroll to the very bottom and click on "Add another Nav item".
4. Fill out all appropriate fields for the new navigation item.
5. Click and drag on the double blue, directional arrows and place it where you want it in the order.
6. To make the nav item a sub menu item, click on the right blue arrow found left of the nav item.
7. Scroll back down to the very bottom and hit "Save".