Now we will position the main 'reference' electrode.

Take another paste filled electrode and, this time, stick the back of the gold-cup in the middle of the exposed adhesive of the tape such that the tape and wire form a 'T' shape.

Affix the electrode to the prepared area in the middle of the forehead with the wire running back over the head.

Ideally the wire should run down along the left side of the back of the head before coming over the shoulder and inserting into the CZ port on the headbox (the 5th input in from the from the front left of the headbox).