This isn’t really a long time in storage. You might not have to do anything. Several of my cars would have a run the battery down in 3 months so if you have electricity in the garage I’d buy a battery tender charger and hook it up to the battery.
I would treat the gas with a stabilizer and since we have ethanol in the gas now, I’d use a marine fuel stabilizer. If the motor is near due for an oil change I’d get that done just prior to shutting it down.
I"d also get it washed just prior to storage so there isn’t road salt and chemicals sitting on the paint. If there is potential for bird droppings (or bat droppings) I’d put a cover on it. Also critters like mice and squirrels can do major damage if they nest in the car. They chew up wires, sound deadening materials, and upholstery cushions; so take some measures to keep them out of the car. A good barn cat helps and sticky traps around the car are good too. Do not put bait in the car as it attracts them before they eat it. If your unheated garage is really more of a “barn” I’d consider another place to store it.