This is an easy job, but unless you know all the hidden screws and plastic tabs you might break the interior, and there are no new interior parts on the market, take care of your door panels.
You need to take off the door panel every time you need to lubricate the window mechanism or clear out the water drains. Or if you need to change the door handle.
Locate hidden screw beneath plastic cover in the inside door handle.
Locate the two screws inside the arm rest.
Pull put the chrome cover and find the third and last screw for the arm rest.
If you are so lucky so unlucky to have a manual window regulator mechanism. You have to pull off the window regulator handle , drag the plastic cover straight upwards from its center to get it off.
Remove the two screws from this door striker chrome cover.
Now comes the tricky part. The front upper corner of the plastic pocket in the door has a plastic clip that sits in the door frame. To get this one off you can not pull outwards on the door! You must first loosen all of the plastic clips around the door edges, and when they all are loose you can pull UPWARDS on the door panel and the clip for the plastic pocket will loose (see image). The only thing that is attached to the car then is the upper edge door panel. Just pull more upwards and it will come off.
The door has a plastic sheet over the door holes to keep moisture from deteriorating the door panel. Because rain water from the outside window runs down into the door slightly between the seals and leave from holes at the bottom of the door. The plastic cover protects moisture from destroying the door panel. The car is not a u-boat and therefore this plastic sheet needs to be there, if it is old, cut out a new one from some heavy plastic and replace. Just use some random glue to keep it in place while putting the panel back on.
As you can see here the edges of the door panel has many white plastic clips, usually some of these old ones break and they are good to have some spare ones at hand.