This is simple on your engine ... go to your local auto parts store and purchase a Chilton's or Haynes manual for your vehicle it will explain how to remove the fuel injectors, relieve the fuel pressure etc. Once you get the injectors out the O rings slide on and off no big deal just time consuming ... two ring sizes and colors is most common!
In this picture you can see an injector and the rings ... http://www.billhughes.com/fuelRail.jpg
Another pic: http://partimages2.genpt.com/partimages/鈥?/a>
Another pic: http://cleang.nismo.org/injectors.jpg
Another pic: http://www.automedia.com/article/images/鈥?/a>
Another pic: http://www.nmia.com/~dgnrg/inj1.jpg
