I need to change the thermostat in a 1993 Jeep Cherokee Laredo

I'm going to assume that you have a 4.0 L6 (inline 6) engine) since that's the most common one. If not, most of instructions are the same. 1. With engine cool, or, pressure out of system, radiator cap off, remove both hoses from thermostat housing (top radiator hose connects directly to housing on front of engine). 2. carefully scrape all gasket material from housing and block. Make note of how the thermostat was installed (end with spring goes into the engine block). Since installation is vertical, I usually use silicone glue on gasket, installing thermostat into housing first, then applying gasket to housing, so that it will hold the stat in place when installing to block. (let glue dry for a while). 3. Put a thin film of silicone on engine side of gasket, position assembly on block and put in the easiest to access bolt, finger tight. Be careful not to move assembly around too much or you may cause the thermostat to go out of position. Put in the second bolt, again, finger tight. When both bolts are installed, tighten each, going back and forth, taking up tension equally (don't tighten one, then the other one all at once). 4. replace both hoses, fill to replace any coolant lost (usually not very much). Start engine and run with cap off radiator and heater full "on". Watch temp gauge.When up to operating temp, add more coolant if necessary. (also monitor radiator during this stage for overflow or overheating. it is sometimes necessary to intermittently add some coolant while engine is coming up to temp. as some overflow is normal). 5. close cap and run for several more minutes. Check hoses and therm gasket for seepage. Some re-tightening may be necessary, but if excessive you may have made a mistake you should not have to "crank down" really hard on any hose clamp or fastener. PS, I usually remove and replace spring type hose clamps with screw type. They are more reliable and easier to work with!
Good luck!