Hm, never bothered to learn all of the e-commerce CMS you've mentioned. That's because you don't need to know all of them when you're running a business say on Drupal only. Moreover this a mostly a work of professional developers who know how to set everything up for us. Let them do their work! Both for development purposes or just for computer science homework help I'm better off sending an inquiry to
https://myassignmentlab.com. That's probably the best solution. While of course if you want to save on third party service then go learn everything yourself.