Through this lecture, I was able to experience not just how to use OpenAI Codex, but also how to apply it to an actual development workflow. It was great to naturally learn frequently used practical techniques starting from basic concepts. In particular, the focus on projects with clear outcomes—such as creating a portfolio site, implementing an STT service, automating crawling, and building a real-time dashboard—rather than simple examples, made it highly immersive. Additionally, it was beneficial that the course covered the differences and usage methods for Codex App, CLI, and Cloud environments, allowing me to use them according to actual situations. I highly recommend this lecture to developers who want to quickly experience the recent "AI vibe coding" trend or to those who want to rapidly build side projects on their own. It was a practice-oriented course rather than just a simple theory lecture.