Your car doesn't have spark plug wires.
The ignition system in your car is an electronic direct ignition system. Each spark plug has it's own ignition coil which sits right on top of the plug. Signals from your cars ECU trigger the coil packs to fire the spark plugs. If you remove the cover that says NISSAN on the front of the motor, you will see the 3 coil packs for the front bank of cylinders. The rear ones aren't covered, look closely between the intake runners and you'll see the 3 coil packs that fire the rear 3 cylinders.
Get yourself a Haynes repair manual for your car at a book store. The Maxima is a very easy car to work on, but you should reference the book for help. Might be a good idea just to breeze through it so you get a better understanding of how your car works.