You arm the motors by throttle all the way down and yaw all the way to the right. The yellow STATUS light should turn solid. To disable the motors use throttle down, yaw left.

If this doesn’t work, you have to make sure the channel ranges of your transmitter go from <1050 to >1900. These gestures don’t work if your transmitter is not properly configured and most do not come with properly configured channel ranges. See the Transmitter Tutorial.