Spark plug remover

Hello, I have two(2) questions for you. First, I have van listed above with A/C. I need to change the spark plugs. First question is, can you tell me what size spark plug socket I need? On the YouTube video’s that I have watched, they tell you to use a 16mm. Is there a 16mm socket? I have a complete MM socket set, but it doesn’t have a 16mm in the set. I have a 15mm (little to small) and 17mm (little to big). What would you use? Second question is, in my Haynes Manual, it said that the three(3) back spark plugs has to be removed from beneath the car, but yet in the YouTube video’s it shows the spark plugs being removed from the top. How would you tell someone to remove the back spark plugs? Thank you, Bill Hewitt.