Reporting on Zephyr Scale

I'm not aware of any guides to help you in this way.  There are help files but they don't offer guidance.  This is quite a large topic to try and handle in a post, but my advice would be to think about what you want to report to your stakeholders and testers, e.g. programme board, management team, test teams/testers, and then structure your test cases, test cycles and test plans to support that.

I typically build a few Dashboards for these purposes and have posted an example for stakeholder management below that uses the "Zephyr Scale - Test Execution - Test execution results (overall)" dashboard part to chart completion status, and, the "Zephyr Scale - Test Execution - Test execution results (progress)" part to chart execution progress by status - I've used these to separate into two rows (In Progress & Not Executed, and, Executed statuses in the other row).  You can achieve a lot with the Custom Query filter and once you've had some practice you will find it easy enough to build dashboards or reports - they both work the same way.