On my first one I used guide pins in the side of the chassis. That mounted to the body were I attached some wood slots for the pins. On my current one the chassis is the same size as the under side of the body, so I was able to to just put a couple screws in the side. I have seen many different ways of doing it I dont know if one is better thatn the other, tape, glue, velcro,ect. Just use what works best for you and the look you want.