To find it, you'll need to:
1. Consult a repair manual: A Haynes or Chilton repair manual specific to your 1996 Chrysler Sebring convertible (and engine size) will show you the exact location with diagrams. This is the most reliable method.
2. Check online resources: Websites like AutoZone, Advance Auto Parts, or similar parts retailers often have diagrams and information about your vehicle. Search for your specific year, make, model, and engine size. Enter your vehicle information and look at the parts diagrams for the oxygen sensors. You should be able to zoom in closely to see placement.
3. Visual inspection (use caution!): The upstream O2 sensor is usually located in the exhaust manifold or very close to it. It's a threaded sensor with a wire harness leading to it. The downstream sensor will be further down the exhaust system, after the catalytic converter. Be extremely careful when inspecting the exhaust system as it will be hot if the engine has recently been running. Wear appropriate safety gear (gloves, eye protection).
Without knowing your engine size (2.0L or 2.5L), I cannot give you a precise location. Finding a repair manual or using an online parts diagram is crucial for accuracy and safety.