From the Mameroom site.
No measuring required and no costly mistakes. Just glue, tape, or trace the templates onto the wood material and cut.
If you want only one cab then glue or tape and cut. If you might want to make another cab or you have a friend who might want a cab then trace. When you trace you have to secure your plans on at least one side (tacks or tape) so it will always be in the same position when you are moving the carbon (tracing) paper around under the plans. Look for the largest sheets of carbon paper that you can get.