Got heater core need to put it in,want to now how to do it the right and fastest way

In order to replace a heater core in a 1998 gmc jimmy the coolant must be completely drained and the entire dash including radio, vents and panel covers must be removed. four screws hold the top portion(closest to the windsheild) in place. they can be found under the windshield defrost vent. after the entire dash is removed a safety harness under the steering column must be removed and the steering column must be dropped to the driver seat. The heater core housing(black plastic) is located right center of the dash and is a two part housing one piece on top of the other. the housing is attached to the fire wall and must detached before replacement can continue. after detaching the housing from the fire wall separate the housing by unscrewing the six screws that hold it together. the heater core is now exposed. disconnect the heater core from the two hoses and discard. installation is the un installation process in reverse.
Good luck, it is a very long and drawn out process that is not accomplished in just an hour or two . make sure you have most of the day or several afternoons to finish . i started this and it took me 2 afternoons to take apart and put back together