The fabric frames are biscuit joined on the edges in a matrix to form frame sections that were then taken down and laid on the floor. A backing cloth was then (same as the backing on a quilt) stretched, spray glued and stapled to the back of the frames using an 1/4" crown air stapler (5/8" long staples) This was done to prevent the insulation from eventually bulging through the frames from the back and pushing on the outside fabric.
The outside cloth was then unrolled on the floor, back facing up and the frames placed on top. (plastic was put on the floor first to prevent and marks on the cloth) The cloth was stretched and spray glued to the back of the frames and stapled using the same stapler. This made it so nothing was visible from the front. The sections were lifted into place and nailed with a 2" air finish nailer, through everything, which leaves no trace on the surface. Each wall in the photos is one section (max length 14’, which I did get help lifting) except for the longest wall (25ft), which was broken into two sections. I then put a solid painted MDF board in between those sections, which you can see in the photos. It will be used for a HT poster, with lighting from above on a dimmer, so not to interfere with the movie. Also, that dimmer will drive a light box above the door going into the theater, which will have a THX logo painted on it (or something)
The bottom sections are raised from the wall with 2x2’s and covered with 3/4" MDF. That was air nailed, glued and filled and then the top raised pieces, cut, routed and glued/air nailed to the top. A crown molding was then added at the tops of the walls, with a 1” gap at the back to accept the cloth framing. The holes were filled and the whole thing including the projector mount, rack, and walls sprayed with an HVLP spray gun.
I am not a carpenter by trade, just what I picked up along the way..