What is the best way to put the drive washer on to the wheel shaft? Every time I try it just falls off.

Is the washer too big for the nut, so it just slips over, or are you requesting a 3rd hand.
If it just a 3rd hand you can tip up the car so the washer falls over the shaft and not down onto the chassis, or a drop of grease is a very useful glue to safely stick things in place while you are doing other things.

If this is not helpful then please explain your question with some detail.

I have it thax anyways