question on how i will go about trading a car i JUST got

[twinz1]

hi im picking up a car tomorrow just to trade it for another car, im gonna tell the guy im buying the car from to JUST sign the title and nothing else... now how do i go about trading this car to someone else for a different car, how do i right the bill of sale ect since i dont wanna sign the title because then ill haveto wait a month for a new one... never did this before so just wondering btw i live in mass thanks in advance!