The monitor I'm using is in the 4:3 aspect ratio, so it isn't widescreen. The reason I chose to do this is because all the arcade and console games from the 1980s and 1990s were in that aspect ratio, and those are the games I'll be playing. The Raspberry Pi 3 uses an HDMI video output (which also carries sound), whereas the monitor uses VGA (which doesn't). So, I picked up a HDMI-VGA converter that, while cheap, did the job perfectly, though not at first. The Raspberry Pi only sends a signal through the HDMI port when it detects a monitor, and it wouldn't detect my older monitor through the converter, so I had to edit some of the settings in the Pi's config.txt file. I made the Pi force a signal through the HDMI port, and it worked. Soon, though, I was faced with another issue: the speakers I had plugged in were hissing. After some research, I found that I just needed to make another adjustment in the config.txt file. The audio automatically had some white noise in the background; I had just had to disable that setting. Now that I had the interface problems solved, I had to start working on the controls. I'd bought six buttons and a joystick, and I had to buy an arcade encoder, too. All of the controls have micro switches, which are connected to cables that plug into the arcade encoder board. The arcade encoder plugs into the Raspberry Pi via USB. This really seemed daunting before I actually did it; there's a lot of cables and pins, but really the process couldn't be much simpler. It's a matter of plugging the right cable into the right pin. What button should be Button 1? Plug it into that pin. The same goes for as many buttons as you have, up to twelve. The joystick is slightly harder to wire, but only because when you push it forward, the bottom of the stick actually moves backwards, towards you. When you push it to the right, the bottom goes to the left, et cetera. So when you plug the cables into the micro switches on the bottom, it can feel like you're mapping the right switch to the wrong pins. After that, though, you just need to plug the arcade encoder into the Raspberry Pi and everything should be good to go. I booted up the Pi and-voila!-all the controls worked. With RetroPie, controls need to be mapped out in the settings, so you can remap any controls you want (which is great for adding extra controllers).