Step 1: Locate low-pressure port. This alone took 30 minutes of research, and another 30 minutes of labor. Here’s the port location on my 2005 Ford Focus ZX4. It’s on the top left of that big silver cylinder. I had to jack up the car, remove the tire, and remove the plastic screw tabs holding the plastic inner fender in place.
Admittedly, Steps 2 & 3 were pretty easy after that. Check the pressure, and refill refrigerant.
Of course, the instructions didn’t account for Step 4: Put your car back together, another 30 minutes or so of labor.
I worked as a driver at my bro-in-law’s repair business for a while. There’s a lot of cars where they put the reservoir cylinder in much more ridiculous places!