To set the output voltage to the desired level, a resistor must be added between the Trim and GND pins. For example, to set the module to output 5V use a 1.34kΩ resistor, or to get 3.3V use a 2.182kΩ. See table 1 in the module’s datasheet for more resistor values.
The ON/OFF pin on the board can be pulled high to turn the converter module on and low to turn it off.
Board comes as shown, with all components (aside from the trim resistor) populated. Access to all pins of the converter module is provided by two, 0.1" pitch headers.