The Github repository includes the KiCAD design files, which you can use to order the PCB and bill of materials. All of the components are surface-mount except for the CR2032 battery holder. Take care when mounting the microphone, as it can be damaged by excessive heat.

The CR2032 battery holder blocks the programming contacts/pads, so don't install this until after you've programmed the microcontroller!

The firmware can be compiled and programmed using the MPLAB X IDE in conjunction with a programmer that supports this microcontroller, such as the ICD4 or the PICKit4 (I have not confirmed support for the PICKit4!).

The PCB has surface-mount pads for accessing the In-Circuit Serial Debugging (ICSP) pins on the PIC18. The Github repository also includes the design files for a programming break-out board with pogo pins and alignment pins. This can be connected to a Microchip ICSP programmer/debugger to flash the microcontroller.

As of now the only supported microcontroller is the PIC18F06Q41. If you substitute another microcontroller, implement the functions declared in the h-files in the HAL directory. Depending on your choice of microcontroller, you may need to run the SignalSamplingConfigurator Python script. Define your microcontroller's peripheral timer speeds, and the script will output the appropriate settings for each musical note.