The top photo shows the corner of my Mianne benchwork looking upward at the bottom of the plywood. You can see the square block, which is glued only to the plywood, that fits into the inside corner of the Mianne framework. I used one block under each corner. This accurately positions the plywood atop the frame, prevents it from moving, and allows the plywood and anything attached to it to be quickly lifted off the layout.
MELGAR