Changing a Stat is not that bad of a job depending on the vehicle and what is in the way. I start off with draining maybe a gallon or so of antifreeze out of my radiator into a clean container before starting so that you can put that same clean antifreeze back into the car when needed. From there you should have 2 bolts holding the thermostat housing to the intake manifold. Sometimes there may be a bracket attached to these bolts so you will need to remove this first. Then using a 3/8" rachet with extension I loosen the 2 bolts and remove them. Then you need to lift up on the Thermostat housing and move it away to gain access to the thermostat. Lift the stat out and replace it with a new one placed down in the manifold the same way. Some stats have writing on them stating (toward radiator). If so make sure you face it the right way and make sure you don't put it upside down. Before inserting your new stat you will need to clean the area where the gasket sits on the manifold and thermostat housing. Make sure the surface is smooth. Then apply gaset cement to the gasket on both sides. Install your new stat and then set the gasket down. Then take your thermostat housing and place it over the stat and place both bolts into the stat housing holes. Tighten up but don't overtighten or you will break the housing usually made of aluminum. Just tighten it a little more then snug. Next with the radiator cap off of the rad start the car and start putting that antifreeze back into the radiator. As the engine gets hot it will except more antifreeze. Once it starts to overflow put the cap on and put the remainder of the antifreeze in the overflow plastic white container usually bolted to the fender. If you feel you can't fit it all just put the remainder to the side and check the car out after driving it and letting it cool usually the next day or hours later. You should be able to fit the remainder then. Good luck.