During the campaign level Gas Station Robbery, follow these steps:
Explore + City
Explore + Gas Station
Explore + Salesman Manny
Watch + Pawnshop
Money + Salesman Manny
Pub + Petrol
Boom! (Literally). Cheev unlocked.
Advice from Spilner:
"If someone already completed the episode, suggestion is to back out to the episode list, press
and then highlight the one you need to redo and press
to restart."