You can now navigate to the front-end of your website and hover your mouse over the Products Menu. Here you will notice the newly created menu item appearing under it. The style of drop-down menus, fold and unfold, the way they appear depends on the Joomla templates you’re using. It is highly probable that your template does not support drop-down menus in case your menus don’t show.
Generally you don’t need to have a parent menu that loads a specific page but you need to have just a container to group few menu items together. You need to create a main menu item following the same steps described above until you have to choose the Menu Item Type. Here, instead of a Single Article you need to select System Links -> External URL.