How to replace the heater core on a 1995 B2300 Mazda truck?

From Haynes Repair Manual #36071, Ford Ranger Pickups 1993 - 2005 and Mazda Pickups 1994-2005 B2300, B2500, B3000, B4000: (1)Disarm the airbag system; (2)allow the cooling system to completely cool down; (3)using a thick cloth for protection, turn the radiator filler cap to the first stop; (4)step back and let the pressure release; (5)once the pressure has been released, completely drain the cooling system; (6) working within the engine compartment, loosen the clam,ps on the heater hoses at the engine compartment side of the firewall, twist the hoses and carefully sepseparate them from the heater core tubes; (7)plug or cap the heater core tubes to prevent coolant from spilling into the passenger compartment when the heater core is removed; (8)place a plastic sheet on the floor of the vehicle to prevent stains if the coolant spills; (9)remove the instrument panel; (10)remove the PCM heat sink and ground strap; (11)remove the heater plenum chamber; (12)separate the heater core from the heater plenum chamber; (13)installation is the reverse of the removal with the following additions; (a)fill the cooling system; (b)run the engine, check for leaks and test the heater.