I have looked everywhere for a good guide for RetroArch and so far yours is the best one that I've found. Thank you so much for taking the time to make this. The only other thing I would like to see you add is controller setup. Mainly because it was so confusing to me until it finally clicked and now I understand it and want to share it for others. Specifically I want to explain that RetroArch uses a controller that they call the RetroPad. (I don't know how to put pictures in my posts but click here for a picture.) As you can see it looks identical to an XBOX 360 controller which is why those controllers will work right out of the box. But what always confused me was figuring out and remembering what button did what for each different system. That was until I came across this site here (scroll to the bottom) which shows examples of other system controllers and what buttons on the RetroPad related to what buttons on the controller you are emulating. The other thing this site helped me with was when trying to map other controllers to RetroArch. For example, I have an N64 controller to USB Adapter and it was always a guessing nightmare trying to map the buttons. Mainly because when you set your inputs in RetroArch it told you to hit buttons like X, Y, or right analog stick which the N64 controller obviously doesn't have. But I was able to use the controller images on that site to help me figure out (for example) that when it wanted me to press the right analog stick it really wanted me to press the C buttons on my N64 controller.
Anyway, I hope you find this helpful and understand what I was trying to say. I'm a horrible writer and speaker when trying to get my points across which is why I don't write guides. lol. But your guide was a very big help in understanding RetroArch and the only thing I felt it was lacking was the explanation of the controllers. Even if you don't feel you need to add it then hopefully at the very least someone else would see what I wrote and it would help them. Thanks again.