If you're like me and appreciate a visual aid in understanding these kinds of concepts, I would highly recommend watching a few youtube videos to understand the theory of it before trying to apply it. Conceptually, I've found
this video (and the whole series) to be really beneficial when introducing new programmers to PID Theory.
Of course it might not technically answer your question in regards to application with a Jaguar, but the concept is really the most important part to grasp.
In addition, search through previous CD posts I'm sure you'll find a more technical answer. Good Luck!