How do I find the pilot light on an older GE Smart Water heater, Model No. GG50T6XA?

There should be an access panel behind the gas valve. Lift and pull off. There will be a small gas line, usually with a small hood, pointed toward a thin, 1/8 " thermocouple. The pilot light, if on, should be visible. If there is no flame, turn the small knob on top of the control valve to Pilot, push down and hold a long lighter or long match where the small hooded line is. It should light. Keep holding the pilot valve down for 15-20 seconds. If it stays on rotate the small valve to on. If the pilot goes out, after holding a flame to it, the thermocouple safety is bad and needs to be replaced. Pretty easy fix. Unscrew or unclip the thermocouple at the pilot flame, pull it out and unscrew it from the gas valve. Replace it in reverse. Most thermocouples are universal. HD or Lowe's. Good luck.