petri[.]com/a-complete-guide-to-robocopy/
No way around it -- it's complicated... So, why bother? Dragging files from one folder to another is quick & easy in File Explorer, but terribly inefficient [meaning slow] if you need to copy a boatload of files. What makes Robocopy complicated is that there are all sorts of options you can use to limit which files are copied, like how new the files are, or how large -- there's even an option allowing you to start where you left off if the copying gets interrupted. Robocopy is a good [maybe even great] way to copy things like game collections, and because it's both popular & well known, if you're unsure which options to use, just Google & you'll likely find just the right answer.