It is basically three parts. I slit the fabric on the underside, inserted some steal plates (door hardware from Lowes) so the shelf 'sticks' to the magnets in the surround. I drilled holes in the shelf and sleeved them with 1/4" black polytube (this did not look as nice as I had hoped for). Then I ran black cord/string (I also have yellow ones) to the plastic surround gap on the tailgate, and slipped a washer in the gap (same concept as my yellow earplug cord in my proof or concept). Knotted and weighted the cord below the parcel shelf.
Works pretty well, and identical in concept to the ones in the thread I linked.