If you are unsure of how to wire something - make yourself a 'breadboard' - a bench top way to simulate your circuit.

You can use your actual switch and relay and and even the driving lights.

Don't forget to simulate the grounds, and to put a fuse in the power wire. (see my other post which has no name on it in your other question.)

After you get everything set, you can connect your project to the car's battery.

That way you can make sure that your wiring works before you cut and install the wires and components in your car.

You can save yourself a lot of time.

Consider an electrical experiment kit - they use springs and pieces of wire with the ends stripped to simulate all kinds of circuits - they are easy to rearrange and you can learn a lot from them.