It's intuitive.
Drain a little bit of the coolant.
Remove the coolant hose from the thermostat housing.
Remove the ground wire.
Remove the two bolts and pull off housing.
Remove the thermostat, taking note of pin orientation.
Replace with new thermostat, correctly positioning pin.
Put it back together and top off coolant.

If you have no clue what I'm talking about, grab a helms/haynes manual or have a friend do it for you.