While the spring and pawls can be replaced on the car, it is much easier to remove the handle assembly from the car first.
Remove the stop pin by lining up the stop pin with the access hole and using a flat punch to drive the pin out from the bottom access hole. Do not twist the stop pin to try and remove it or it will break due the knurling on the pin.
Remove the handle shaft, the old pawls and the spring from their tube.
Place the new pawls in their slot as per illustration and place the new spring over the tabs as you slide the pawl in place.
Holding the pawls up, re-insert the handle and tap the stop pin into place.