Lots of resources by just searching google or the forum
Odometry
Odometry | Purdue SIGBots Wiki
What is Odometry? - #19 by DylanMashini
What is Odometry? - #23 by tabor473
https://www.youtube.com/watch?v=GEZBYHVHmFQ
Uses either “odom pods” (extra wheels mounted on your robot connected to rotation sensors) or your built-in motor encoders and an inertial sensor
PID
PID Controller | Purdue SIGBots Wiki
VEXCode PID Tutorial
https://www.youtube.com/watch?v=_Itn-0d340g