Write the next sentence in the following story.

How to change spark plugs in a renault clio mk3
Park up your car on level ground and wait for your engine to cool down.
If the engine is already cool you can begin work on your car.
Disconnect your car battery.
Make sure your battery is disconnected before performing any work on your electrical system. You don't want a shock or even worse to fry your on board computer because of a shock.