Is your car still under warranty? If yes, I'd let the dealer do it. There are a lot of breakable parts in there.
If not, I looked in the manual and it requires several steps.
1) Remove mirror glass, it just pops out, but be careful you don't break it. A search for installing aspherical mirrors should find some instructions
2) Remove mirror upper case (housing). There are a few tabs to be bent with a screw driver. They should be visible after removing mirror glass.
3) there are then 2 screws that mount the lower trim piece (where the light is). Then you will be able to see the wires and the bulb to test.
Good Luck
Don