Because the first generation PlayStation 1 was so large, and couldn’t really be hidden inside the toaster oven very well, it was screwed in the bottom and covered with a sheet of thin aluminum with a hole cut out for the disk reader and slots for the controller and memory card ports. The glass that was originally shielding the front of the toaster was replaced in favor of some quarter-inch acrylic again with some slots cut out for the controller and memory card ports. Holes were cut in the back for the power, AV cables, and other unnecessary connections and everything was screwed into place.
The electrical additions include some radio shack buttons wired into the place where the PlayStation power button was, some amber LED strips wired into a 5V line found on the console, and a potentiometer in series with the LED strips to adjust the brightness. The power buttons were hooked up so that they were engaged by pressing down the toast lever and the potentiometer placed behind the temperature knob to so it looks like you're controlling the toast temperature.