Place bar in your fixture and set wood up against it to get axle hole for back axle in the correct location, 5/8″ from the eventual back of the car.

Place bar on edge of a length of 3M tape
Cut off excess and use to cover plate weights plus a strip across the back where the bar will go

All the rest of the details and tips come with your purchase. You get full instructions on how to get your car up to speed with all the design improvements over the last 40 years. The latest Pro improvement is “Tuned” tungsten from TxW. The strange thing is while the Pro cars have gotten increasingly faster, the average Cub Pack speed has dropped as the number of folks with tools has dropped. The average car gets the axles pounded in with a hammer into the existing crooked slots, does not add much weight except some worthless zinc, and doesn’t even use any lubrication. This is a District winner from 1980 , 2nd at the Texas State Scouts Jamboree, that has many advanced features that make it a winner still today.