Unreal C++ is well organized by looking at the Unreal docs. It helped me understand the Unreal Engine better and gave me a sense of what I should study further. When I do a personal project, if there is a concept I forgot, I go through it while looking at the article organized in Part 1. I think this is a lecture that will help you create your own Unreal docs. I recommend it if you are new to Unreal Engine!