by the looks of things it operates on a free channel, connect the 3 wire black plug to a spare channel on the receiver, the lights come on and off via a switch on the TX (CH 5 or 6 normally) and a water leakage alarm (VERY useful)
Google translated
Graupner, specialized feature set, 1961 The Special Functions can bow projector and navigation lights, remote controlled via an electronic part, be turned on and off. Moreover, penetration of water into the submarine - with the aid of a sensor on the electronics - a red light activated . The set includes: electronics with cable kit, 1 red light, white light 1 position, 1 bow projector with lamp, extension cord with water sensor and wiring harness connector
Only thing that worries me is the power connection (Red female connector).... I can find no reference to the voltage requirement but i would suggest trying 6v first then increasing the voltage