ProGCC V3 Blank Board Firmware Install
Hold the golden button down while plugging the USB-C cable into the PCB.
A window will pop up containing "INDEX.HTM" and "INFO_UF2.TXT"
Copy the downloaded "PROGCC_RP2040.uf2" file into the folder. The controller will automatically reboot when the firmware is installed.
Go to your settings on the Nintendo Switch
Then scroll down until you see "Controllers and Sensors"
Press A, then scroll down to Pro Controller Wired Communication
Press A, you will recieve a prompt about NFC functionality, press A once again.
You now have Pro Controller Wired Communications enabled.