Glue the back to the sidesThe back is curved in two directions, and I don't have a workboard that is curved both ways. I've tried several methods, including rope and long strips of inner tube. I've found that the best method for me is a large number of cam clamps. I clamp at the neck block and tail block first to to ensure alignment of the center seam. Then I quickly fill in all the way around the back.
The body sits on my guitar-shaped workboard hanging off the edge of the bench. It is shaped like a guitar so that I can get the clamps in close.