Remove the big batt cable, remove the small power wire. There are 3 bolts holding in the starter, yes the heads of the bolts are 12pt. You'll easily see two of the bolts, the 3rd is directly ontop from where the bottom bolt is (pain in the rear). Yes the starter will pretty much drop down between the frame rail and engine.
Once you have the starter on the bench, remove the rear cover on the 'doghouse' of the solenoid. You'll see the contacts right there. The rest will be self explanatory from there.
-Mike