Relay Board Layout:
At the bottom of the circuit board there is a diagram of the relay's outputs. The screw terminal closest to the corner of the board is the N.C. output. The center terminal is the C, and the innermost is the N.O. output. In most cases you will be using C and N.O. If your prop requires +DC voltage to trigger it, you must run the voltage through the relay to deliver it to your prop.
The small black piece is a jumper connector and is used to have the voltage regulator engaged or disengaged. there is no need to change this jumper setting, and improper voltage levels sent with the jumper removed can burn the module.
The piece of electrical tape does serve a purpose. This unit can also detect light, the piece of tape is covering up the light sensor. The adjustment screw closest to the light sensor changes its sensitivity. If it detects light within these settings, the microphone sensor will not work so we have it covered up with tape.
If you look at the images near the adjustment screws you will see that next to the light sensor is a clock. That is the relay timer (how long you want the relay activated when it is triggered), and the adjustment screw nearest the microphone is the volume threshold/ mic sensitivity level.