1) Prize off the plastic mirror trim panel from the front edge of the door, ( this is inside the car).
2)This should expose some screws (2 if you have electric mirrors). Unscrew these, remove the mirror cover panel and disconnect the wiring plug which is now exposed.
3)There is an additional small round plastic cover on the front edge of the door, which you need to prize off to expose the mirror lower securing nut. Then unscrew all three mirror securing nuts, and withdraw the mirror from the door.