You will need to first remove the battery's cable from the hood. Turn the ignition key to the "off" position so as to be able to pull the lock cylinder out of the ignition switch. Put the new lock cylinder I place and insert the ignition switch cavity so as to secure the cylinder. Once you are done tighten the clamp and close the hood. Read more details at http://www.ehow.com/how_5892163_replace-ignition-lock-cylinder.html.