A decorator needs to learn all his life, because there is no limit to the art of decorating. If you take a separate cake decorating course in school, you can learn the basics in 20 days. Once you have the basic skills, you will also have the skills. Technology is easy to master, but art requires gradual practice and accumulation of experience in the future. Skill is the foundation!
No matter how many patterns you learn in school, you will never be able to finish it. This requires daily practice and lots of ideas in the future!