* Consulting a repair manual: A Chilton's or Haynes repair manual specific to your 1996 Chevrolet Lumina will have diagrams showing its precise location.
* Using an online parts diagram: Many online auto parts websites (like AutoZone, Advance Auto Parts, etc.) allow you to look up parts diagrams for your specific vehicle. Search for your Lumina's VIN or details, and you should find a diagram showing the EVAP system's components.
* Visually inspecting: With the vehicle on level ground, look underneath the rear passenger side (near the fuel tank) for a cylindrical canister with various hoses attached to it. Be cautious when inspecting under the vehicle.
Remember to be careful when working under your car and use jack stands for safety.