In this section, we'll set up the navbar items for our site pages, and we'll also go ahead and add the markup for the navbar.
Click on the Customize button on the theme page again. Under Menus create a new menu called Main navigation, Check both The main menu as location and Automatically add new top-level pages to this menu under menu options:
Then add some items under the menu. Select both the Home and Sample Page under the Pages option:
Now press the Save & Publish button and close the customizer after that.
The main navigation ...