I've done the frame for the Japanese puzzle quilt. I stabilized the thing by ironing it to freezer paper, and turning under the edges of the outside pieces. Then, after figuring out the length and width of the border, I carefully placed the quilt down on paper cut to size and marked the angle lines. Next I retraced the pattern and added seam allowances, cut the pieces out and stitched together.
It went together very smoothly, and sounds simple to tell, but figuring it out was the hard thing. I have learned a lot about putting odd angled pieces together, if nothing else! The next thing is the tedious, but straight-forward job of appliqueing the body of the quilt to the frame. Keeping it straight and flat will be the main problem. I hope lots of pins will do the trick.