theres other how to's with real pics too. take a search for them.
what the whole crappy job amounts to is removing every gold bolt you see around the bottom of the hvac box there, theres 2 layers.
and of course, leap frogging from one side to the other removing these bolts.
a good flash light or small drop light is a huge help, as you cant see jack for a lot of the bolts.
a beer or two to loosen yourself up helps, as well the aspirin for your back when done.
i dont know if it said so in this how to. but take the hoses off the alt bracket, and blow the core out, this way you dont spill any in the car when taking the core out.
and on the firewall from the inside is a screw holding the two tubes to the wall. you can see it sticking out on the outside of the fire wall between the in and out lines. thats the last bolt you'll get out. then the core will come out.