Is there a diagram of where an O2 sensor is on a 1996 Chevy Beretta?

There are two of them on a 1996 Beretta. One is mounted in the rear exhaust manifold. You should be able to see it by looking under the hood, straight down the back of the engine. The other is located just before the catalytic converter. Poke your head under the car and look for the big "bubble" in the exhaust pipe closer to the engine.