How do I change the spark plugs on an Audi A6?

I've noticed my car is running rough and I have a feeling it may be due to old spark plugs. How can I change them myself at home?

Step 1: Make sure the engine is cool and remove the engine cover. Step 2: Locate the spark plugs and use a ratchet and extension to remove the old ones. Step 3: Check the gap on the new spark plugs and install them. Step 4: Replace the engine cover and start the car to test the new spark plugs.