Changing the propeller blades is something the normal handy manage with only a 5 or 6 mm allen key (depending on the propeller size). We recommend that the propeller is mounted away from the motor and the switch takes place on a solid surface.
Loosen and remove the four screws (7) from the propeller. Make sure the adapter (1) is in place so that the nuts do not fall out of their grooves.
Remove the ring (4) and the rear hub (3) so that the blades are accessible, remove the broken blade (-s) and install a new one.
Replace the rear hub (3) and ensure that all the blades vanes ports in the respective recesses. The pieces shall easily fall into place, use no violence.
Adjust all the blades so that their vanes are positioned in the middle of the hub part / recess. Then mount the ring (4) so that each blade guide vane is fitted in position in the ring. Compress the propeller so that all parts fall into place.
Make sure the adapter (1) and the front hub (2) is in place.
Mounting the screws and tighten them slightly so the ring (4) has a little gap from the hub part. The ring (4) "teeth" that engage with the rear hub (3) shall be visible.
Set the pitch as shown in the separate manual.
Tighten the screws, hard and firm, without using accessive force.