You can set your navigation buttons at anytime, though it's best to wait until you have some content to link them to.
In the builder, at the bottom of all of your pages, you will see four gray boxes. Click on each box to set the navigation buttons. The editor window on the left opens. Choose the page that the navigation button will link to and choose a related icon. Next you'll, most likely, want to have a short Title that will accompany the icon, e.g., Home, Map, About Us, Sites, etc. You don't necessarily need to set every navigation button, you can choose to have a two, three, or four button navigation just by leaving it blank.You can elect to show only icons or text, simply, don't set them.
You may set up to four buttons. Since these are quick access buttons for your user, we recommend setting a minimum of two.
Use the red "Clear Nav Button" to reset the button to inactive.