How do I change the spark plugs and where are they located in this car?

Honestly, when someone asks this question, especially with the 3.4L V8 in the Taurus SHO, I absolutely must suggest you take this car to have a professional perform the tune up. Too many things can go wrong to have an inexperienced hand work on it. These cars are just more sophisticated than the cars of the 70's or earlier which were basic and simple.