Each spark plug is located beneath a coil. It's called a coil-on-plug (COP) arrangement. Unfasten the connector to the coil and use an 8 mm socket to remove the coil's mounting bolt. Here are some tips that may help you replace the plugs, especially those in the rear:

https://www.askmehelpdesk.com/cars-t...ml#post1375876

https://www.askmehelpdesk.com/cars-t...tml#post617111

My advice is to only use the same Motorcraft platinum plugs that originally came in the car and be sure to check the gap; otherwise the CEL may come on indicating a misfire. Attention to detail makes a difference on these cars.