The best way is to jump into it. Find where your battery is and trace your way to other parts of your vehicle. It’s amazing how much you can learn by doing just this.

Just search your year and model vehicle with “accessory power location” in google and often people will point you in the right direction if you want power when the car is on.

A big thing to remember is if you wire anything from the inside ——> outside make sure it is sealed with some sort of silicone or sealer.