Insert large plastic shim into the deck bag by rolling it up widthwise (not a tight roll, just enough to fit into the opening), inserting it into the middle of the bag, then let go. The shim will automatically spread to the outer edges of the bag and create a supportive arch.
Move the shim to the middle of the bag for the best overall support.
Place the deck bag in an accessible position on your boat, then clip to the deck lines to secure. If you do not have deck rigging on your kayak, please contact your local dealer or NRS for the hardware to install your own.