In a Report Set, you can request any number of reports and extracts, and any number of instances of them with different reporting options specified. For example, you might request three variations of the Performance List report, one Performance Summary report, and two different Cross-System Work extracts.
For Report Set JCL generation, you must specify the systems that you want to analyze. The systems and files must be defined in System Definitions. You can link directly there by selecting Systems in the action bar.
It is recommended that you specify your System Selection at run time, not within the Report Set. This will allow you to run your Report Sets against any of your defined systems.