I am not seeing the same thing on my backend as in the video. In our menu area, even though we have Mega Menus visible and functional on the front end, there is no option for Mega Menu  in the backend. If I add a new menu item from the Categories section, one that has existing subcategories, no Mega Menu options appear. Please see screenshots.

Our current header menu has sub items that appear with images that link to blog posts in that sub category. We want to add a new item with new sub category items, but when we do, it just appears as a simple drop down without images. How do we set up a new sub menu to appear like the attachment?