The Collaborative Research Center Open System Control of Atomic and Photonic Matter (OSCAR) explores the physics of open quantum many-body systems across different experimental platforms. Apart from basic research in this field the integrated young reseacher training program i-OSCAR guarantees education of the highest quality standards for the involved doctoral students and early postdocs. As a particular educational measure our SFB organizes an International School on Open Quantum Many-Body Systems, which takes place in the Evangelische Adademie in Tutzing (Germany), in the period April 1-4, 2025. The lectures focus on three research areas, which are of central importance of OSCAR and will be discussed from both the experimental and the theoretical point of view.