First, undo the two screws, one at the bottom of the door pull, and the other hiding behind a plastic plug in the middle of the door opener handle. Phillips, I believe.
Next, get a slim pry tool like a flat pry bar and release the door panel starting at the bottom of the door. They're just a bunch of plastic zip rivets that click into receptacles, and they'll just push back into place when you put the door panel back on. There are several of these rivet thingys around the door. Just take your time and pry the door panel off.
You'll need to unplug the electrical controls, which is just a plug. Also, the speaker unplugs too, IIRC. I can't recall exactly how the door handle rigging disconnects, but it must be simple or I wouldn't have been able to do it.
The skin under the panel is easy to get off. Peel back enough to get your arm in there and undo the door check. The check itself is just on there with screws, IIRC, and no problem to access. The part that bolts to the door frame is self-explanatory. Stretch the skin back over when you've got the new door check in place. Then replug the electrical plugs, and the door handle rigging, and replace the door cover and the two screws.
The whole operation including putting it back together took me about half an hour. Give it a shot! If you run into any problems let me know, or somebody else will help.