1968 dart wiring harness help

In the yellow circle looks to be the main splice.
If its in good condition, support the wires so there is no strain or untwisting and rewrap it.
The main splice joins the alternator and the battery feeds, and the feeds the other systems.
When the battery is hooked up, those wires are always connected to power. Do not let any of the conductors ground.
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Schematicly functions like this.
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