The method shown in MissionPlanner works well and doesnt need you to do anything with your transmitter. The flight controller calibrates the ESCs using the RCin values from the radio calibration you would have already done.
Other simple way to callibarate pwm ESCs without using RC in APM 2.8 flight controller. Just go to parameters and change ‘RC3_MIN’ from 1100 to 1000 and plug in battery. Your ESCs will be auto-calibrated on every boot.