TOP NYLON PIECES ON THE JIG ARE TO HOOK OVER TOP OF GLASS AND PUSHED DOWN ON THE GLASS WITH NO GAP TO THE “U” SHAPE IN THE NYLON BLOCKS BOTH SIDES AND BE CENTRED ON GLASS WITH NYLON PIECES ON SIDE TOUCHING THE EDGES OF THE GLASS- THESE MUST BE FULLY SEATED TO TOUCH THE EDGE OF THE GLASS- IF NOT REJECT GLASS