Find out how we want to help you as a developer, and plant trees here
A comparison between Divi and Elementor by CollectiveRay, it's a decent comparison of the two products, the author essentially boils it down to the difference in pricing as the primary distinguishing factor.
A beginner level course about the Divi Theme. The course covers the basics in a fair amount of detail, and although it's not an advanced Divi Theme course, it does cover a couple of more advanced subjects or features.
A beginner focused course over at Udemy for the Divi Theme. The course takes the follow along approach, taking you through building a few different page examples of a simple site. The instruction is clear and easy to understand, if you're looking for a beginner course on the Divi Theme, this is one of the better options.
A short but sweet guide as to how to use the Divi Builder plugin if you don't want to use the Divi theme.
https://www.elegantthemes.com/gallery/divi/(about affiliate links)