NSS / backup lights question

I think the other thing that's confusing me is how the lights will get power.

The way I'm seeing it is that I have a single purple wire going to the driver side backup light, and a second single purple wire splitting off and going to the passenger side. If I plug the NSS harness into the trans, and run the two outer wires into the single purple wire going to the back, exactly what is powering the lights?

Likewise, if the white wire is coming from the wiper switch on the dash, should it go back into the socket on the column? I couldn't see or feel any wires coming from the socket (or on the column on the motor side). So what's applying power to the switch for it to work?

Maybe I'm missing something here.