You need to make sure the dial in your door arm rest for the mirror is pointing at the passengers side mirror and then when you put it in reverse it will dip. I leave it in this position unless I fold the mirrors in or need to use the heated option but I always set it back to this setting. Passenger side mirror on the dial
To set the angle of the mirror, put the car in reverse and then adjust the position so it is right for you ( for me it's so I can see the curb and back tyre). Again leave the dial in this position.
When you drive away it will take a few seconds or over a certain speed to go back to normal