You buy the bodies as clear lexan shells. They come with window masks and all the stickers for headlights, park lights, etc depending on the model you have selected.
Then you mask out the body using the window masks, on the inside of the body, and use masking tape to mask the patterns that you want. Then you spray the body on the inside. Then strip the protection sheet from the outside and the colors show through brilliantly. You then put on the headlights, etc and any stickers that you want.
There is a little more to it, but you can look in the body painting section for that
