I downloaded Dune but can’t find it in msfs to fly in it. What am I missing.
Heads up: I’ve moved your topic to the appropriate section of the forum. 
The content included in the Dune expansion can be found under the “Activities” section in-sim. You may have to scroll through the different activity options to find it.
The Ornithopter can be flown in Free Flight mode, and is selectable from your hanger.
Hope this helps!
You also have to download it (free) from the Marketplace.