If you are using a battery for power, the black "negative" jack, located on the back of the unit near the DC inputs,  must be grounded by plugging in the black ground wire and connecting the other end to a suitable electrical ground. If you are using the AC power converter, the unit is already grounded through the power supply. Do not ground the red output under any circumstances.
The pilot light located on top will light up when there is a high voltage output. The light becomes brighter when the correct frequency is attained.

  CAUTION! DO NOT ALLOW THE BLACK HIGH VOLTAGE CABLE CONNECTED TO THE HIGH VOLTAGE OUTPUT TO TOUCH ANY OTHER WIRES, METAL OR PEOPLE. THE VOLTAGE IS VERY HIGH AND CAN ACTUALLY GO THROUGH THE RUBBER INSULATION
Warning: All persons touching or handling plates or electrodes that are connected to the unit must not touch any metal and must be away fromall ground sources such as a faucet, a metal sink, or a metal beam. The subjectshould not sit in a metal chair or on a metal table. The subject and operator should be insulated from ALL metal.

The high voltage that the unit supplies can give you a slight burn if you come close to the output and the spark jumps out to you. It is important that both the subject and the operator do not touch any metal or any other person.

DO NOT PUSH THE PULSE BUTTON WITH NOTHING CONNECTED TO THE HIGH VOLTAGE OUTPUT- DAMAGE MAY RESULT TO THE UNIT. A PLATE OR ELECTRODE MUST BE CONNECTED TO UNIT.