It looks like your thermostat is on the engine where the lower radiator hose connects. This is unfortunate, because you may have to drain the radiator before you remove the hose.
After you get the hose off, you'll see 3 bolts holding the housing on. Remove them and you should see the thermostat. It's very important to pay attention to which way the thermostat is facing, as the new one MUST go in the same way. Replace the gasket, put the housing back on with the bolts and then you'll have to refill the radiator with a mix of 50/50 coolant/water.
You must then run the vehicle with the radiator cap off until all the air has bubbled out. Be very careful, it will get very hot.
My advice...pay to have it done. It's a mess if you don't have a shop to work in.
〉 Answered on Apr 14th, 2007 by Lori Johnson, Owner and Instructor at Ladies Start Your Engines