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I'm trying to install an Alpine HU by myself and am wondering how to go about locating number 1 and 7. Is #1 easy to find because it's already attached to my stock radio's back? As for #7, how do I find such a wire? I know how to use a circuit tester, but have no clue what wire to check.

Lastly, with regards to #8, do I have to snake a wire all the way to the battery terminal or can I just split the existing power wires from the cords to the stock radio?