How do i replace the heater core in a 1983 oldsmobile cutlass supreme

The heater core is located under the dash board on the passenger side there is a few cap screws holding this black plastic box that hides the heater core loosen all the screws .take the plastic out of the way and u will see the heater core .there are two hoses to disconnect on the out side .under the hood on the passenger side .up near the fire wall .the re is a avaperation tank silver in color for the a/c under that there are two heater hoses to disconnect .when u remove the two hoses .they will leak antifreeze .bend the hoses over to kink them .tie some elec tape around them to keep them from leaking .go back in the car and loosen the four small screws that hold the heater core in place and remove .....in stall the new one the same way .taking care when putting the new one through the fire wall not to damage the brass tubing ...mount heater core first the place hoses on after the screws are holding the heater core in place then put plastic cover on start car and wait for thermostat to open .turn heater on hot .after water is circulating .refill radaitor ...job done...