[How to do instruction] Use hardware momentary switches to control moOde

[Britracer]

Tim, I want to use more GPIO than you have in the GPIO handler - where do I find the config file. I assume I leave the GPIO button handler off in the system config menu. I have 8 radio presets that are encoded as BCD, so use 3 GPIO, but this requires a little more programming of the GPIO.
Can you point me in the right direction please as to the file I need to create and where I will find it.