So, just like a hoop coop, really.
Wire all over, solid or wire ends, tarp or roofing (plastic or metal), and ventilation.
Here are a few inspirations that use arches other than cattle panels:
https://www.backyardchickens.com/articles/low-hoop-coop-chicken-tractor-pvc.76361/...
We'll be able to say more later with the pictures, but it sounds like you can use the same sort of techniques people use for hoop coops. You can do a search on the coop pages to get ideas. :)