Once the cover has been temporarily removed, you can apply your socket wrench. Place the spark plug socket into the spark plug hole, use the wrench to turn counter-clockwise until the old plug is loose. You'll know when it is loose enough by periodically pulling out the socket gently. The spark plug socket will have a magnet inside of it to hold onto the plug once it has become entirely loose of the vehicle. Ensure that you are wearing heavy duty gloves. Then, replace the socket with the new plug. The gloves can be important here, because your older plugs may still be a little hot if the engine was on earlier (that is, before you had opened your front hood). Put the new plug in the hole, turn clockwise, and screw her in. Do not screw her in too tight nor too loose. Screwing her in too tight could cause the plug to break or be damaged in some way. If the plug is in too loose, then one places the risk of the spark plug shooting out when the vehicle is started later on. And, that could start a fire and be very dangerous to more than just yourself. Please keep in mind that not only your own safety is involved here. Now, one may put the rubbery cover back on. You should make sure that this is placed in very firm; we really don't want to start a fire or even scare the neighborhood cats. Repeat the necessary steps with the remainder of your spark plugs until they are all finished.