When you import a demo, the default menu that links to the main demo's pages will be imported as well. To create a custom menu that better suits your website's structure and content, follow these steps:
Step 1:
1- Open the menus tab from Apperanace --> menus
2- Create a new menu
Step 2:
1- add name to your menu
2- check the "Display location" checkbox so it be selected on all the pages automatically
3- hit the "create menu" button
Step 2:
1- select the pages you want to add then click "Add to Menu"
2- Arrange Menu Items: Drag and drop menu items to arrange them in the desired order.
3- Click "Save Menu" to apply your customizations.