Reverie : How to edit the navigation menu
You might want to read this guide first on how to create a navigation menu in WordPress.
On your WP Dashboard, navigate to Appearance > Menus to start editing your menu.
You will see that Reverie has four menu locations in the demo. Two of the menu locations are for each side of the split navigation on the header, one is for the mobile version, and the last one is for the footer (optional).

Please remember: Adding items to the Primary and Secondary navigation menus doesn’t automatically include them in the Mobile navigation menu. If you want a menu item to appear on the Mobile menu, you’ll need to add it separately.