Under the hood, most likely near the battery, or on the inner wheel fender, drivers side, you should find a black, mostly square plastic box. You should also be able to see a lot of wires (the harness) running into the bottom of it. Take off the cover (if you need tools, it’s not the right box). Turn the cover over in your hands, and look inside it. You should see a diagram of everything in that box, and what it does.