This is the menu which appears for desktop versions of the site. This is a really powerful menu as it comes with an inbuilt mega menu.
Method 1 [ Does not support mega menu creation ]
Simply head over to customiser and create a menu and assign it to the Primary menu location.
Method 2 [ Supports Mega menu creation ]
a. Go to WP admin – Appearance – Menus
b. Create a new menu and assign it to Primary menu location