How do you change the heater core in 1984 cutlass supreme with air conditioning?

To change the heater core in a 1984 Cutlass Supreme with air conditioning, first, disconnect the battery and drain the coolant from the radiator. Remove the dashboard and the HVAC assembly, which involves taking out various panels and components to access the heater core. Once exposed, disconnect the hoses and remove the old heater core, then install the new one, reassemble the HVAC system, and finally reconnect everything, ensuring to refill the coolant before testing the system.