Our performance management process was set up for us and now I need to change it, but I can't find a

I need to change our performance management process - the timing, some of the questions, and how it ties in to goals. I can't find instructions ANYWHERE on this topic- SuiteAnswers questions only refer me to managing the performance of the app or platform itself, not how to administer the performance management portion of SuitePeople.

Accessing through Setup/Performance Management, I can choose Performance Review (which provides me a list of all the reviews in the system done to date), Review Category Detail, and Performance Due Dates Config. There's absolutely no guidance as to what a "review Category" is or how it will be integrated, just a screen where you can add.Ditto for Review Date preferences. Does anyone have an overview of the setup process?