Remove the gear (2nd) that is over it. Then you'll see a pin that holds the clutch in place.
The little spring, silver ball are parts that provide the tension to the clutch arm. There should also be a small grub screw as well, but that must have come out already since that it what holds the screw/spring in. None of those parts are needed at all. You might also want to pop out the plastic plug while you're at it. See the pic below:
The pic also mentions the ball, spring, etc. ;)