Need to know how to change turn signal bulb in drivers side mirror on 2004 VW beetle?

In older VWs there's an opening underneath where you could stick a thin flat screwdriver. Then you would move a piece that would resemble the cap on a jar. If you turned it either clockwise or counterclockwise, it would come to a point where the glass mirror itself would pop out. You would then have access to the inside of the mirror assembly. It may be the same on your car. Good luck.