Customizing Firmware Before Flashing

[coby]

Hello,
I am trying to add a door open/closed sensor to the Heltec WiFi Lora V3 board and update the firmware to use the pins on the board and be able to send a message if the status has changed.

My primary question is where the changes to the firmware would need to be made given the board that I am using. I initially tried adding code to the Loop in 'src/platform/esp32/main-esp32.cpp', but this doesn't seem to be correct.

Thank You!