The Clueboard is one of the officially supported keyboards in QMK. If you want to customize the firmware for your Clueboard you should start there.
QMK Configurator (Start here)
For a nice friendly way to build your keyboard's firmware check out the configurator:
QMK Source Code
For more advanced use cases you can use the QMK source directly. To get started checkout The Complete Newbs Guide To QMK.
How To Enter Programming Mode
Getting your Clueboard into the "programming" or "bootloader" mode is easy. By default you can press
Fn+S+R to flash your Clueboard. If you are not able to use that for some reason you can also use the
RESET button on the bottom of your PCB. If you have an Alumunium case this is the button that is exposed next to one of the screw holes.
Fn+S+Ron the Keyboard
- Press RESET on the bottom of the PCB
Flashing A Firmware File (Windows and Mac)
Use the QMK Toolbox to flash your Clueboard: