Attaching the rear runner boards is pretty straight forward.
Use anti vibration rubbers on the frame struts either side of the scooter. On the outside of the strut, use a rectangular rubber like so...
...on the inside, where the bridge piece will fit, use a round rubber...
...and a final round rubber on the rear outrigger dogleg bracket.
Place the rear runners on to check fit and placement as well as making sure all the holes line up.
Before checking the bridge piece. Also make sure that the runner boards will be level with the flattest part of the legshields when tightened down. If they are a little low, you can use an additional rubber washer. They should fit perfectly if your dry build was accurate before painting.
You will need 10 x 8mm nuts, washers and 8 speed clips (spring clips) to affix the runner strips.
Attach the inner strips with the runner boards OFF the scooter.
Attach the outer stips by fastening the centre captive bolt only.
Attach all the speed clips.
Now make sure the two end bolts of the outer stips are lifted up and offer the runner boards to the scooter and work it in to place. Push the two end strip bolts through the rubbers and strut/outrigger and fasten down.
This picture below is just a test fit to make sure the outer strip fitted properly. It was a little tight, but did slot in eventually.
Ensure the fit is right and level before final tightening.