This iBM Support web page describes IBM i system tasks and what they are used for.
This IBM Support web page describes many of the IBM i system jobs,
This IBM Support web page provides an introductory overview of the Work Control Block Table (WCBT).
This article provides an overview of what workload groups are and why you should use them.
This article explains how to “tune the tuner” using Work with Shared Pools. This Experience Report does not look to be available after 7.2; you may want to download and save the PDF.