The pictures and the procedure of this DIY is based on the 993 door panel with the factory 10 speaker hi-fi option, there maybe some minor difference in procedures to take off the door panels of a none 10 speaker hi-fi optioned 993.

(1). Use a philips screw driver to remove the door panel screw around the bottom and the side of the door panel, and remove the screw inside of the door pocket.  The below pictures will show the approximate location of these screws.

(2). Once you have removed all the screws the bottom portion (speaker panel) of the door panel should pop right off easily.  If it doesn't come off do not force it off, check for additional screws.  Once the internal speaker box is exposed you can unscrew the screws that hold the speaker box to the door.

(3). Pull the speaker box forward and disconnect the connection to the back of the speaker box. 

(4). Pull on the door handle and pop the door handle hinge up to release the door handle.

(5). Unbolt the three 5 mm (I think that is the right size) allen bolts on the door handle

(6). Now the door panel is ready to be pop out.  There are two strategic spots where you would apply the pulling force to remove the panels, and that is on the either side of the panel.  The below picture shows you where the plastic pop rivet is located at on the door panel.

(7). You will have to unplug the windows switch from it's wiring harness when you remove the door panel at the same time.   When re-installing the panel you can install the panel first and plug in the windows switch later.