You can go to the Appearance Menu on the left side of your admin page, and select menus. From here select a menu to edit, and select the Custom Links section. Now just enter the link you want to redirect to, the parent site for instance, and give the link a name, like Back To Main Site or something. Save it and you’re done. You can edit everything about your menu and link structure and maintain multiple menus such as a main menu and a footer menu, from here.
