I'm going to assume you're referring to the stock fog light switch on the light stalk on your steering column.
I don't have a step by step instruction here is how you can do it:
1. Use a voltmeter to find out what wire on the stock fog light harness is power
2. Clip off the stock fog light connector (keep track which wire is positive)
3. Clip off the white connector on the piaa lights (wire going to the bulb is positive, wire going to the housing is ground)
4. Splice corresponding wires together
I have slight OCD so this is what I did:
1. Use a voltmeter to find out what wire on the stock fog light harness is power
2. Clip off the white connector on the piaa lights (wire going to the bulb is positive, wire going to the housing is ground)
3. Spliced the piaa lamp wires to the female end of this:
Halo Automotive WH9006 Plug and Play Upgrade Wire Harness and made sure the correct wires match the stock connector