I did that something like thirty years ago, so the details are a bit fuzzy. Four-pin HEI ignition module mounted to a heat-sink somewhere on the inside of the unit, primary wires of perhaps 18-gauge leading from the W and G terminals to the exterior of the cabinet. They'd connect to the mag pickup on the distributor. Polarity matters, you want whichever way works best--which generally provides the most advanced timing.
The B+ and C- terminals got connected with 14- or 12-gauge primary wire to the "ignition" coil + and - terminals that powered the strobe light. Kinda thinking there was a ballast resistor in there, so the B+ would connect on the higher-voltage side of the ballast resistor. (Check the voltage available. The HEI module should be good to 17 volts at least short-term, 14-ish preferred.)
I must have provided a ground wire from one of the ignition module mounting screws to the chassis of the machine.
I don't remember how--or if--I provided switching for the normal "points" triggering vs. the mag-pulse triggering.
I did all this when I thought I'd "invented" a way to put a Chrysler reluctor and pickup coil on a GM points-type distributor, and needed a way to check my work. About a month later, I visited a "speed shop" in the larger town eighty miles away...and found someone was selling a ready-made "electronic conversion" kit for GM distributors using Chrysler parts, to do what I'd just accomplished grinding by hand.