You'll see where the end of the wire is wrapped around the strut at the base of the ball. The wire has the end bent back to create a rounded tip. Pop the loop off of the shaft, then slide the pin straight out the end. The ball should come off the mount if you lift the weight of the hatch off the strut and give it a yank. Thump the new one on and replace the pin (if your replacements have the same style retainer).