Please go to the Menu section, create a menu and then select the newly created menu from the Theme Locations box from the left.
Does your site have a compelling reason why buyers and sellers should choose you? If not, then you are missing the boat. Buyers and sellers want someone who they can trust and connect with on an emotional basis. Yet most "about us" sections, if they even have one, read like corporate-speak and have photos that would be better suited for "wanted posters."