The rapid advancement of Artificial Intelligence (AI) necessitates its active integration into the secondary school curriculum. This article explores effective pedagogical strategies for incorporating generative AI tools, specifically ChatGPT and Midjourney, into school Computer Science lessons. Moving beyond traditional computer literacy, the study emphasizes the importance of teaching students how to interact with AI safely and creatively. The paper outlines practical methodologies for using ChatGPT to develop algorithmic thinking, understand prompt engineering, and debug code. Concurrently, the application of Midjourney is analyzed as a powerful tool for fostering digital creativity, visual design, and bridging the gap between technical skills and art (STEAM). Furthermore, the article addresses crucial ethical considerations, including academic integrity, AI bias, and cyber hygiene. By presenting practical lesson frameworks and case studies, this research demonstrates that teaching AI not only enhances technical proficiency but also cultivates essential critical thinking and modern digital citizenship among students.