[Alan Anderson]

BROWN: PDB +12
BLACK: DI SIG
BLUE: PDB (-)

The three wires coming from the device should be brown, black, and blue. Connect brown to +12 volts (a red Wago terminal on the Power Distribution Board) and blue to power return (the adjacent black Wago terminal on the Power Distribution Board). Black is the signal output. Since the device you linked to is an open-collector NPN transistor output, it can be connected directly to the SIG pin on a Digital Input on the Digital Sidecar. The built-in pullup resistor on the sidecar will pull the signal to 5 volts when the sensor is not active, and the sensor will pull the signal to ground when what it's sensing is within 2 mm.