Two ways:

1. Quick (Theme: Navigation) — put the page address (pages/<slug>) into Custom Link 1 (or 2), give it a Custom Link name, and tick Custom Link 1 (or 2) in Pages to show on header/footer. For About, Contact, FAQ, Terms and Privacy use their dedicated Link: … fields instead.
2. Full control (Menu Builder) — in Menu Groups (/admin/menugroupbuilder) create a group (Title, Menu Position Header or Footer) and activate it; then in Menu Builder (/admin/menubuilder/<group>) set Select Menu Type to Existing pages, choose your page from Select Default Pages > Custom Pages (system pages, meal and product categories are also offered in that same dropdown), enter the Title and click Add menu item. Drag items in the current-menu list to reorder or nest them; the position saves automatically.