I don't like to disappoint you but it is nearly impossible to learn startup simply by attending a course. My advice would be to focus on competencies that can help your startup grow. For example, digital marketing courses, marketing strategy seminars, and business etiquette classes (in case if you want to negotiate a lot or attract investment) can be tremendously useful for you as a startup entrepreneur.

In case if you need any advice on the topics mentioned above, just let me know and I`ll be glad to help you to recommend the best