Supplemental Navigation is a page level navigation element. Intended to be used in combination with the primary navigation element.
Step 1: From your template insert a new element as "Navigation - Supplemental" found under "1 - Responsive Elements"
Step 2: Define the element by clicking the gear icon where you placed the element in the previous step.
After selecting a header and orientation there are many styles to choose from. Classic is a black font on a white background, while default is purple on white. Home page is the same as default, except it makes the purple text bold. Gold 1 and Purple 1 give their color respectively to the background and have a black font. The rest of the color styles only appear as backgrounds when hovered over by the mouse.
To mange the links you can click the add link button to add another link to the list. The text field is the text that will show up for the link, while the url field is the url that the text will link to when clicked by the user.