You can take a course on QuickBooks ®. You will no doubt learn a lot. But again, questions will arise. Like what applies to your business and what does not?
You can always ask the instructor. But he or she has only so much time to get through the material, deal with your questions and deal with the questions of your classmates. Also, you have only so much chutzpah to apply to the task of getting all your questions answered.
When the course is over, you're on your own. What do you do then, when new questions arise? Or when you're no longer sure about the answers to the questions you've already asked?