Easy, Ben! Consult the circuit diagram. Relay K1 is supplied with +12V. It then feeds either +RX or +TX as the case may be. The underside of the board has the pads to connect to, either to individual LEDs with series resistors to 0V or to a 'bi-color' LED with resistor from its common lead to 0V. Those voltages can be accessed on the top side of the board by locating resistors in the 'bi-amp' section/s and carefully attaching your wires. The traces there follow the circuit diagram. A little mental effort, but well worth it. I'd suggest only a TX LED - if not lit, the rig is is Rx mode. If your kit is non-Raduino, I'd suggest a 'Power on' rather than 'Rx' LED.
73
Dex, ZL2DEX
