I came across a couple of videos of my listening room taken before it was covered with acoustic fabric.
They provide a good view of the wooden framework and the large amount of absorptive material used throughout the structure (Caruso Iso Bond).
It is probably easier to grasp the overall concept from these videos than from the finished room, as everything remains visible.
The pictures :
→ https://photos.app.goo.gl/2DPoRdCEKvT3K2yk8