Instructions
Turn on your Xbox 360 and wait for the Kinect to finish booting. A black and gray image appears at the bottom right after the Kinect finishes booting.
Stand in view of the sensor and wave either arm until the Kinect recognizes you. The Kinect Hub opens.
Hold your hand over "Sign In." A list of your Xbox 360's accounts appears.
Hold your hand over the account you wish to sign in to. The Kinect scans your face and signs you in to that account. Repeat steps 2 through 4 for additional users.