How do you change the spark plugs on a Ford Fiesta duratec?

To change the spark plugs on a Ford Fiesta with a Duratec engine, first, ensure the engine is cool and disconnect the negative battery terminal. Remove the ignition coil by unscrewing any bolts and gently pulling it off the spark plug. Use a spark plug socket and ratchet to unscrew the old spark plug, then carefully install the new spark plug, tightening it to the manufacturer's specifications. Reattach the ignition coil and reconnect the battery terminal to complete the process.