You can configure menus in Drupal 8 by following these steps:
1. First, go to the Admin Toolbar and click on “Structure.“
2. Here, you will find the “Menus” option, click on that.
3. You can create a new menu by clicking on the “Add Menu” button. Enter a name for your new menu and click on “Save.“
4. You can add links to your new menu by clicking on the “Add link” button or you can select an existing menu from the list of menus and edit the links in the menu.
5. When you click on the “Add link” button, you will need to provide details like the title of the link, URL, and if you want it to open in a new window or not.
6. You can also create dropdown menus by adding links to the parent menu and then dragging and dropping the child links to the parent menu link.
7. Once you have finished adding or editing your menu, click “Save” to save your changes.
That’s it, your menu should now be configured on Drupal 8.