How do you change a thermostat on a 93 Ford Laser?

To change the thermostat on a 1993 Ford Laser, first ensure the engine is cool and disconnect the negative battery terminal. Drain the coolant from the radiator, then remove the upper radiator hose connected to the thermostat housing. Unscrew the thermostat housing, replace the old thermostat with a new one (ensuring the spring side faces the engine), and reassemble the housing and hose. Finally, refill the cooling system with coolant, reconnect the battery, and check for leaks.