I had the same kind of signal unit on my 50 Chevy. Somewhere I found a wiring diagram online, but I don't remember where. This unit wires into the parking lights and brake lights I remember that. Mine was old and the contacts were corroded - but eventually I got all functions to work properly including the 4-way flashers. Does your have that feature? I will look for the wiring schematic.
Look at this
here and the image or 2 previous and next.
