1) Make sure that the power is turned off (power switch on the rear turned upwards).
2) Connect the mono line output jack to a line audio input (in e.g. an amplifier or mixer) for monitoring.
3) Connect the MIDI input on DROID-3 to a MIDI output on a keyboard or a sequencer for sending MIDI notes on MIDI channel 1.
4) If you have not done so already, connect the power supply to an outlet and afterwards to the DC connector on DROID-3.
5) Now turn down the volume on your amplifier or mixer and turn on DROID-3 by setting the switch to downwards position.
6) Start playing and slowly turn up the volume to a suitable level. If you have connected the DROID-3 correctly the green LED should now light up for each MIDI message. The red LED shows the audio output.