P0340 Fault in 1996 Toyota Camry 2.2L 4-Cylinder: Diagnosis and Repair Guide

My 1996 Toyota Camry 2.2L 4-cylinder engine has been running poorly, especially at low RPMs, and suddenly stopped starting yesterday. It previously struggled to maintain speeds above 5500 RPM, with intermittent stalling when the throttle was pushed too hard. Now it won't start at all. The check engine light is on, and the fault code displayed is P0340 — Camshaft Position Sensor A (Bank 1) Circuit Malfunction. I'm trying to understand where this sensor is located and what steps I should take to diagnose or fix the issue. Any advice would be greatly appreciated.