We do our design and sewing.
The snaps come in different mounting forms; for around the hatch, we use the base snap with a screw for mounting. Carefully drill a correct hole, slightly smaller than the snap screw; also wrap a piece of tape around the drill bit so it doesn't go in too deep.
For the material, we use a two piece snap, mounted through a hole in the material, then lightly hammered together. There are 3 or 4 of these on each side of the hatch cover, which then push on to the snap bases previously screwed on each side of the hatch.