Typically GM uses a series up push in fastners that run around the outer edge of the door panel on three sides. The fastners twist into the back of the door panel ( which may be cardboard ) the tapered stud end presses into the steel frame of the door. These fasteners are removed with a tool known as a " Fork " available at most auto parts stores. The V slot shaped opening in the fork goes around the stud and when you pry outward it pops it out of its hole. Other prying methods using screwdrivers or something else usually results in tearing the fastners out of the back of the door panel, sometimes damaging the cardboard to the point the fastners will no longer go back in the back of the doorpanel. You need to slide the fork in behind the door panel, slide it around till you find a fastner then back out a bit and try to hook the slot of the fork around the tapered stud.
Next, you may see some screws around the trim plates, or in the armrest depression where your finger slip into when you close the door. You may see some 1 inch or deeper holes bored into the door panel that may also hold a recessed screw.
Some door panel, use snap in parts for trim plates, window button pods, etc.. If you have a seat belt going into the door then the trim for that would most likely need removing too.
Typically the door panels are hooked tt the top of the door, some snap in and need a good jerk to get them released.
Once you got the door panel off then you will have to unplug all the electrical connectors for the power windows, mirrors, door locks, seats, speakers, etc..
If your going inside the door then the plastic water sheild will have to be peeled off.
========= Harryface =========
1991 Pontiac Bonneville LE 3800 V6 ( C ), Black/Slate Grey _~_~_~295,033 miles_~_~_
~_~_~_~_U.S.A._~_~_~_~_~_
~~~The Former Fleet ~~~
89 Cavalier Z 24 convertible
78 Holiday 88 coupe
68 LeSabre convertible
73 Impala sedan