The book helps alittle. However, its pretty easy to find. If you pop off the plastic cover and look behind the engine where the rear exhaust manifold is at, the manifold O2 sensor is right behind (toward the back of the car) the middle sparkplug. Should be a dull silver cylinder about 3-4 inches long, 1/2 in diameter. The wires come out of the top and are plugged in to the harness attached to the metal brace that is sticking up in the middle back there not doing much. This may sound weird, but will make sense once you stick your head back there. I'm not sure where the second sensor is, pretty sure it might be easy to find under the car by the cat. If you're changing these yourself, a GM O2 sensor socket is very handy, they have a big notch in one side for the wires to go out so you can use a ratchet rather than an open end wrench. Try to borrow one, or about $5, which ever. Hope this helps.