The Nu-Vois III has multiple buttons.  The two large buttons on the front of the unit are the power buttons. The two small buttons on the side of the unit are used to change the volume and/or the tone.

1. Before starting, decide which power button to set (top or bottom).
2. Hold down both of the smaller buttons on the side of the unit.
3. Continue holding down the small buttons, and push the selected power button.
4. While holding the selected power button, release the small side buttons to change the tone:
   • To go up in tone, continuously press the top small button;
   • To go down in tone, continuously press the bottom small button.
5. Release all buttons when desired tone level is reached.

Note: The Nu-Vois III has 33 total steps in tone.