Hi,
My code is just an example and you shouldn't copy paste it into your arduino.
You will need to change the pin configurations, the PID coefficients, ESCs calibration config, etc
For arming it depends of your ESCs calibration. The code will work with my ESC calibration but you need to change the code or change the calibration of your esc to make it work. Try to arm one motor without any prop attached first.
And I will say it again, don't copy paste, change only the pin config and hope that it will work. The quad may start and then it will crash after 1 sec..