If there is no menu set, there’s a fallback menu. The sections available for this version of the theme are: About, Works, Testimonials, Team, Contact. For each of these sections, you should create a menu entry with the following link structure:
https://www.yoursiteurl/#about
https://www.yoursiteurl/#works
https://www.yoursiteurl/#testimonials
https://www.yoursiteurl/#team
https://www.yoursiteurl/#contact
Simply go to Appearance > Menus > Create a new menu. After you’ve created your new menu, locate, on the left side, the “custom link option”. Proceed to add the links to the menu with the above link structure(#about, #works, #testimonials, #team & #contact). The labels for these links are at your own choosing, only the link destination has to be as detailed above.
Don’t forget to check the new menu as a Header/Primary menu on the bottom of Menus pages