Drive an anchor straight down into the ground as close as possible to all four corners of the shed. Insert the half of the shaft of a ratchet or large screwdriver in through the opening at the top of anchor for increased turning leverage. Bury the anchor until only the open eyelet is above ground.
Cut the shed tethering cable in half. Form a small loop that runs through the opening at the top of an anchor on the same side of the shed with one end of each cable. Secure the loops with the clamps that came with the kit using a Phillips screwdriver or pliers.
Run both of the half-anchored cables up through the roof of the shed so they go over the largest support beams and cross one another in the center. Simply run the lines over the top of the roof so they cross at the top center if the structure is sealed.
Pull the positioned lines tight from the other side of the shed. Thread the lines through the opening at the top of the driven anchors. Double the lines back over to form loops around the anchors and secure the loops with clamps.