Hi @adb,
The Basic ESC calibration process is very simple- there is none. By default max throttle is fixed to 1900 μs, neutral to 1500 μs, and max throttle reverse to 1100 μs. There is no calibration process, as the option to do so is disables in our configuration of the BlHeli_S firmware.
If for whatever reason you need to use the ESC in a system that requires calibration, you can enable calibration by programming the ESC firmware configuration with BLHeli Suite. The calibration process is outlined in the BlHeli_S manual.
-Adam