Use the provided gerber files to get the PCBs fabricated. Use 0.6mm thickness of the PCB. Lead-free or gold coating recommended, as the device will be touched by hands.

Solder all the components. The QFN chip can be soldered by drag-soldering the edges, though a hot-air gun or hot-plate are recommended for convenience. All the other components are easily soldered by hand.

Get the UF2 bootloader from the link in the hardware repository readme, and flash it onto the microcontroller using a JLink programmer or compatible. The SWD and SWC pins are marked 1 and 2 on the connector at the bottom of the device. VCC is marked + and GND is marked -. Use a 12-pin male header to friction-fit it into the connector and a breadboard for a reliable connection while programming. Power can be provide through the USB connector, make sure the switch is in the USB position.

Once the bootloader is flashed, a PEWBOOT disk will be available over the USB. Download the latest CircuitPython firmware from circuitpython.org and copy it over to that disk. The device will reset and the CIRCUITPY disk will become available.

Copy the main.py file from the software repository, and copy any game files from the pewpew github onto the device.

Safely remove the USB disk, and disconnect the device. Insert a battery.