How do I take a car door apart for a 2003 Toyota Matrix?

On the inside trim, you can remove screws (these screws may be covered by filler pieces or may be visible, or they may require you pry a plastic piece off that covers the screws) that are by the door handle, arm rest, under door and side of door and then gently pull back on the panel as there will also be retaining clips attached and you don't want to break them. You'll need to lift the door panel upwards in order to get it off the window ledge. Then you'll need to manipulate the panel and disconnect the door handle linkage from the door handle and disconnect the wiring for your controls.