I just finished the job and this is what I did:
Take your time, following the process below about 6 hrs and this includes talking to your wife, playing with the dog, a cup of coffee and cleanup.

1. remove the heater hoses from the engine
2. with the hood up use a prop rod of your choosing, remove the passenger side hood support. Be sure to have a big balled up towel or soft carpet for the hood to rest against. and put a paint mark to realign
3. Remove the heater hoses from the heater core
4. Remove bolts that hold casing in at the top
4. Jack the car up from the passenger side frame rail behind front wheel
5. remove front tire
6. Take  fasteners out of front fender skirt 9/16. Pull the skirt down carefully not hitting anything. You can totally take the skirt out or
move it enough to gain access. This will give you access to the bolts on the bottom of the case.
7. Remove the cover
8. Remove heater core
9. Clean area
10 place heater core in position in the front half of the case along with insulating gasket.
11. You can come from the top and position the core and start several of the fasteners.
12. from the bottom side do the same. Check alignment
13. torque all bolts.
14. I attached the hoses and put the hood support back in place. I did this so if the car dropped fast as the jack was released there
would be no damage to the paint.
12. replace fender liner
13. Put wheel on, filler radiator, fire engine, and heat.

Hope this helps. - Gerry Silka