How to get Xbox controller's rumble working?

[JuhJuhButt]

I am not sure how to get the rumble working. I have Motor L and Motor R in the "configure output" window, but when I select one and test, there's no feedback on the controller. Furthermore, I can't add both motors without the error "Expected end of expression." I'm new to Dolphin, so sorry if I sound dumb.

[ExtremeDude2]

Post a picture of how you have it configured.