OK, solved.. Anyway this method is a bit “hidden”… you should make it more… clear! 🙂
After items have been added to a menu, drag and drop to put them in the order you want. You can also click each item to reveal additional configuration options. You can also drag a menu item a little to the right to make it a submenu, to create menus with hierarchy. You’ll see when the position of the drop target shifts over to portray the nested placement.