You can show a single category or categories gird or slider.
Go to your site admin and add a new page and edit the page with Elementor.
Drop the category element and you should see the output. Make sure you have some categories and also have some ads in those categories.
If you are using a single category element you have to select a category from the drop-down.
Note: If you import our demo, you may not see the categories as you see on our demo site. You have to set your category from the drop-down. Also, make sure you have some categories on your site and have an image on the category.