Tack up cloths/towels/blankets to protect the surrounding area – Tape whatever you do not want chalkboard painted.
Make sure you have good ventilation – open doors, fans, face mask etc…
Lightly sand the surface of the fridge
Prime the fridge and let dry according to primer instructions
Spray the fridge with chalkboard paint (I prefer the spray paint over the can – your call) – let the coat dry. Repeat this process, drying in between each coat. Do NOT hold the can too close or you’ll have sad drips running down your fridge that make it look like it’s crying.
Once you’ve sprayed the fridge with chalkboard paint, and are happy with the coverage – allow it to dry completely.
Turn a piece of chalk on it’s side and rub it down the entire surface of the fridge. Wipe that off with a dry cloth, or one of those antique things… you know – a blackboard eraser ? This primes the surface for your chalk writing.
Notes
6 years later the only issue is that the paint on the handles wore away, but that's quickly fixed with a light re-spraying of the chalkboard paint