If you're talking about the material getting floppy once you extend the awning all the way, here is what I found.
If you stand under the awning, with it open, facing the door, look up toward the roller in the upper left corner. You'll see a hole that accepts an allen wrench with a red +/- arrow around the hole. I believe turning in the direction of the negative arrow, tightens up the material.
In your second post, you added a rattle....that requires adjusting the 7/16 nut adjustment on the arm. This time, while under the open awning, facing away from the door, look up where the arms attach at both ends of the outer cover, the part that is not fitting and rattling. There is a 7/16 lock nut that you loosen. It allows the arms to slide out farther on the outer cover. The farther out you slide the arm, the tighter the cover closes. This takes small adjustments on both sides and can be aggravating. Here is a photo of the nut you need to loosen. Mark it's position with a sharpie and move in small increments. Changing one side too much, moves the cover either too far back or forward and it won't seat like it should.
Don & Mary
2019 Newmar Dutch Star 4018 - All Electric
2019 Ford Raptor Crew Cab