Testlink: Create Custom Report

Im new to TestLink and im trying do create my own custom report for the "Testreports & Metrics"-Section. Sadly there is so up-to-date solution to this problem, only many step-by-step guides from 2012 which dont work anymore and even in the current user manual 1.9 there is a small section dedicated to this subject (Screenshot of User-Manual Section), but some of those folders/links don't exist either.

If anyone has ever made a custom report in TestLink or can help, I would greatly appreciate it.

Cheers