First of all, make sure to let the engine cool. Then, disconnect the negative battery cable for safety. Drain the coolant from the radiator (or engine block) into a clean drain pan. Now, assuming that you are replacing a bad water pump, you will need to remove the old one first. Remove the fan and fan clutch making sure to check the fan blades for any defects that might indicate it needs to be replaced. Remove other components as necessary to make the water pump accessible (consult your owner’s manual, if needed). Remove the heater and bypass hoses that connect to the pump, as well as any hose fittings that thread into the pump. Remove the bolts attaching the pump to the engine, noting where each one came from for correct replacement. Remove the water pump from the engine. Clean off the old gasket material from the mounting surface and the bolts. Lightly coat both sides of the new gasket with gasket sealer and place it in the correct position in the engine, lightly coat the threads of any bolts threading into a coolant passage with a non-hardening sealer. install the new pump, attaching the bolts in their original positions (by hand), give the shaft a quick spin, and then tighten the bolts. Reconnect any hoses or components that were disconnected, checking for tightness, close the radiator drain, add the proper coolant mixture and then reconnect the battery cable. Start the engine to check for leaks, making sure that your heater is on to assure circulation of the coolant. Run the engine without the radiator cap until normal temperature is achieved, then top off the radiator and replace the cap.