Welcome to the forum!
I assume you are talking about this:
I don't see prices, but is the retail cost in the range of $1,000 to $1,300 or so?
Seems steep, but IMO it would be hard to duplicate on one's own, and get all the parts and details right. [edit -- see the thread linked below for only so-so reviews of the Zip Dee tropic room]
Have you considered a free-standing screen room? We had one of those in the 90's and it worked great, however the fine mesh screen does tend to cut way down on air flow.
Sorry no personal experience on the tropic room to fit under the awning.
PS -- FYI -- A recent thread with other threads linked therein:
PS2 -- Here is a recent one listed in the classifieds FYI:
Maybe the same one?