Pictured is the back of your door panel once removed. Notice the white plastic clips around the edge. Notice that many are missing. There should be several more on this door. Also, notice that some are broken.
Once the panel is removed, there should be a plastic vapor barrier between the panel and the door shell. This will need to be removed. If removed gently, it may be able to be reused. Otherwise, replace it with any thick plastic and 3M Spray Adhesive or contact cement. (Not pictured)