I followed this guide for doing manual multi material printing with my Prusa printer but do whatever works for you.  You can also just print it all in white and it will work just fine or even stick to a breadboard and skip this step.

Make sure the Arduino holes line up with the pegs, the buttons fit through the holes, and the buttons don't hit the top of the case when fully shut.

Lay out all of the parts in the bottom of the case and then tape down the LED strip and hot glue the right button in place (make sure it is still aligned with the hole in the top of the case).  You could get away with not taping or gluing but I found it made things easier.  I also pre-measured and bent all of the wires so I knew they would fit but do what works best for you.

See the schematic for details, but the important wires are:

• Right button connects to D10
• Left button connects to D3
• LED connects to D2

If you wire it up wrong or want to pick different pins you can always change the pins in the code

// Define pins being used
#define LED_PIN 2
#define RIGHT_BUTTON_PIN 10
#define LEFT_BUTTON_PIN 3 

Plug the Arduino in to your computer and upload arca1d.ino sketch. Currently there are menu Booleans that need to be toggled and re-uploaded each time to switch games but I'm hoping to eventually have a menu.

// Menu fields
bool playStacker = true;
bool playPong = false;

Once you know everything is working close it all up! I glued the case together with a little hot glue but it should have a pretty decent pressure fit.