"First off, and most importantly what is the pitman arm and where is it?"
It connects the steering box output shaft to the steering linkage.
"How could I tell if the wheel is turning before the pitman arm moves? Do I need somebnody in the car to turn the wheel while I look?"
Yes. If necessary, drive the car up on blocks at the front, but the wheels must have their normal vehicle weight. The steering wheel is turned back and forth JUST to the point where the wheels show movement. You look at the entire linkage for signs that some things are moving and others aren't, or are moving in a direction OTHER than what their bearing should allow. This won't be so helpful for diagnosing looseness in the steering box or coupler, but will allow you to take care of the rest of the linkage first.
'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7