Theme uses three menus which are provided by Drupal:
To manage menus and menu items choose Structure > Menus form the toolbar. (
You can add a new menu using "Add menu" button, or you can modify an existing menu by clicking on the "Edit menu" button.
Step 1: Click on "Edit menu" button to edit Main navigations menu
Step 2: Click on the "Add link" button to add a new link, or click on the "Edit" button on the link you wish to change.
Always enable "Show as expanded" option on a parent menu items, otherwise your parent links wont expand in the off-canvas navigation.