Converting points to a pertronix electronic ignition

I went to change out my points and condenser ignition on my 68 225/6.
The original coil had the wire from the distributor connected to the +on the coil and a wire from the wiring harness connected to the - coil terminal.

What do I do with that wire? Is it the wire from the ballast resistor that several articles say to connect to the coil? Per the instructions, the red from the eleconic module is connected to the + on the coil and the black wire to the - side.

I'm not sure I understand the explanations on connecting the ballast directly to the + side of the coil.

Any suggestions would be greatly appreciated.

Thank you For A Bodies only!