I don't remember exactly all the steps but I do remember you have to remove the glove box, the glove box door, the dash pad, then you need to remove the ducting and the big black box on the firewall. You will need to drain the radiator down some before you undo the heater hoses from the firewall side as well. I can't believe your name is the exact same as mine and you are working on the same type of car I own.
When I was young and my parents owned this car I remember doing these heater cores so often that we had it down to under 2 hours, remove and replace. I think a Haynes manual might have some help for you too.