Holybro Pixhawk 4 S500 V2 Basic Kit - Calibrate Electronic Speed Controllers; ESC Calibration Procedure

For more information about the flight, modes visit this link.
https://donlakeflyer.gitbooks.io/qgroundcontrol-user-
guide/content/SetupView/FlightModes.html
Step 6
Calibrate ESC
Step 7
Press calibrate.
Connect your battery and when the end of the tone, press ok and unplug the battery.
Warning: propellers must be removed from the vehicle prior to performing ESC calibration!