How do you change the plugs on 2009 highlander?

To change the spark plugs on a 2009 Toyota Highlander, first, ensure the engine is cool and disconnect the battery. Remove the engine cover if necessary, then locate the spark plug wires or ignition coils and carefully disconnect them. Use a socket wrench to remove the old spark plugs, inspect the new plugs for the correct gap, and install them by hand before tightening them securely. Reconnect the ignition coils or wires and the battery, and check for any issues before starting the engine.