You wont need supports but ensure your bridging and extrusion multiplier is properly dialed in. Everything fits but it is a tight fit to keep it from falling apart.
Everything should be printed in the orientation the files are in.
Bill of Materials (BOM)
Wiring it all up.
Refer to the image to see how I wired mine. No resistors are needed as there are pullups on the board.
Solder one wire between one leg of each button, and the corresponding IO port on the Arduino. Connect a common ground wire to each of the other legs of the buttons, and terminate it at the GND pin of the Arduino.
Everything is a press fit. Push the Arduino into its slot. If you are using a USB adaptor, push that through the slot until it plugs into the Micro USB on the Arduino. Push the Button Lid down into the casing and push to fit. It will stop flush with the top of the casing.
In case of wiring errors, use the little cutaway to pry the lid off. See? I'm helpful sometimes ;)
Open the Arduino editor (Desktop or Online will work fine). Find the correct model you are using, which should be "Arduino Leonardo" and find which port it is plugged into on the PC. Load in the provided code and hit "Verify". If all goes to plan, it will be successful. Then hit "Upload" and wait a few seconds for all the magic to happen.
To program macros, I used AutoHotKey (https://autohotkey.com/) which has some great tutorials for beginners!
Please, if you have any problems drop a comment and I will help you as fast as I can!