Attaching bracing and bottom:
The box lining is attached in place, along with the vibration damping (either bitumen or rubber sheets) prior to assembly. Access will be limited later. A staple gun comes in very handy here.
Gluing first curved segment:
Many clamps are used, not only to apply pressure but also for adjustment. The use of CNC panels does not make a good result certain. If not correctly assembled, the box may not end up square. The diagonal clamp in this picture is used for adjustment.
Long clamps are required in a project like this. I'm using 1m clamps here:
The glue ooze is expanding polyurethane glue. It's expensive and harder to work with, but necessary in certain places. Why is it harder to work with? Even getting it out of the bottle needs more effort, firm pressure is required. Gloves must be worn, since it's very difficult to clean off your hands. If you get it on your hands, washing immediately will usually not get it all off.
Dowells added as bracing and the top also goes on: