Actually, the speaker goes as depicted below. There are three extra pins that are for an external volume control as this board doesn't have it on-board. There are the red block on the right. You can either use those pins with an external control or buy the proper volume control pot and solder it to the board locations for it. You can also short two of the pins for max volume and dispense with the volume control. For steam, a reed switch goes between the Trigger switch and DC Common on the lower right connector. The 5VDC is for a hall effect sensor.
