Once you installed Theme Native, all menus were automated created. You can find them in Appearance >> Menus.
Create pages so you could assign them to appropriate menu. For instance, we create two pages – Who we are and What our customers say about us. Then we find them in Appearance >> Menus >> Pages and click Assign to menu About us.
Visit Site and you will see your new menu ready. Do same to configure the rest of menus.