Editing in souce code

ArduCopter
,
1

Hello everyone,
I have a confused ,I want to setup the Arducopter in Ecilpse ide i could not souce code file in arducopter.
So ,My question are:

  1. Source code file for add the code external sensor
  2. develop the code
  3. HOW TO SETUP PX 4 toolchain
  4. Building the build of ardupilot in mission planner
  5. Suggesting any documentation.
2
  1. Downloading the Code / Using Git — Dev documentation
  2. Learning the ArduPilot Codebase — Dev documentation
  3. Building the code — Dev documentation and Editors and IDEs — Dev documentation
  4. What are you asking here?
  5. Welcome to the ArduPilot Development Site — Dev documentation
3

Thanks for reply
I check it

4

I did not find the source code file of ardupilot main.c file