Here's a '68 diagram showing the main circuits and headlights (Barracuda/Valiant/Dart?). @dukeboy_318 This is a good example of redrawing a factory diagram to focus on a specific circuit or two.
If there's something here you can't follow, then ask.
Think of it like a water hose. Voltage/water flows from the spigot/battery, towards the earth, ground. Diagrams only show the hot wires, the positive side. The negative side get connected to the chassis, a common ground.