The project "I already know!" aims to increase the competences of young people in assessing the credibility of information found on the Internet. In the era of more and more frequently encountered disinformation, young people often do not know how to distinguish truth from falsehood. By conducting courses on source assessment and manipulation recognition, a debate with decision makers and creating a report on a selected manipulation, we hope to provide participants with both the theoretical background and practical skills needed to navigate the today's world of electronic information. This will combat widespread propaganda, populism and radicalism, and reduce the effects of harmful narratives such as vaccine skepticism, anti-democratic attitudes, racism, xenophobia and discriminatory attitudes among the young.