First step is to carve all parts.
I used one sheet of multiplex plywood in this case it was 600 × 300 mm and had a thickness of 12 mm. If the material is thicker you get a wider car.
All parts are carved on one plate.
take car to clean the holes for the axis.
The axis is a round bar of 10 mm diameter, i glued one Tyre into place. After its dry i put the axis in, dryfit the other Tyre and cuted the axis to lengh. Afterward i glued it up.
This step is the most intense. If you are worked precise before it will be easier.
You have to sand everything i started with 120 grid and ended be 320.
You can sound the edges if you like.
At the end I coded my car with furniture wax.
The other car you can see in the picture got some patina before by using chalk paint.