Standing on the left side of the, look down through the engine bay where you'll be able to spot the arm and lever for the pull start mechanism.

Pull on the cable from inside the car (get someone to do this if you can't reach) and you'll see which cable moves.

The end of the cable has a long notch in it (top of photo) that fits into a metal finger on the arm/lever. It should be held on to the arm by a split pin. Pull this out with some long nosed pliers and the end of the cable will be freed.

Next, undo the brass coloured flathead screw (lower down the cable), to completely free the cable from the arm/lever.

The screw fits into a square fitting on the underside of the brass tab. Take care not to lose it when you unscrew it. I suggest putting a magnetic dish underneath to catch it if it falls.