Vex Coding Studio PID Help

I am trying to figure out PID. Can someone help me start where I need to?

PID is intended to maintain a certain motor speed. I’m sure I will be corrected if I am wrong but I thought it was built into V5 and VCS.

LeftMotor.spin(directionType::fwd,120,velocityUnits::rpm);     //< Spin at 120 RPM.
vex::task::sleep(15000);
LeftMotor.stop();