The PCM computer is behind the glove box. You empty out the glove, push in on the sides, and allow the box to drop so you can access the area behind it.
Look at the PCM location and go out of the car under the hood and find the big wiring harness plug in the engine bay that plugs into the pcm through a hole in the firewall. The middle of the wiring harness plug has a bolt in the middle that fits into a threaded hole in the pcm unit case to keep them attached securely. You have to turn the rounded bolt end by hand until it is free spinning and then you can pull the harness plug from the pcm. Go back in the car and there may be a small plastic clip with a screw or bolt that supports the pcm that needs to be removed to get the pcm out. Sometimes I have seen the small clip already missing from people messing around with the pcm.
Lots of words but unbolt wiring harness before you try and pull it free, get pcm from interior behind glove box. very simple.