Push the cord through either of the attachment points closest to the middle of the kayak.

You may use a pen to help guide the cord through if it doesn't go through easily on its own.

Tie a simple overhand knot to secure the cord on this end.

Thread the cord through the opposite attachment point and then to the next point on the opposite end and repeat - Creating a criss-cross pattern as you thread away from the center of the kayak.