This video shows you step by step how to calibrate your ESC throttle endpoints with Cleanflight or Betaflight and BLHeliSuite. Here are some related videos that you might also want to watch:
https://www.youtube.com/watch?v=spegU... - How to manually calibrate the top end of your throttle curve. This is something that the calibration method in this video will not accomplish. For some people, this step is the only way of finally getting smooth motors at high throttle.
https://www.youtube.com/watch?v=4z7yR... - How to build a current-limiting bulb adapter to protect your ESCs while you are working on your copter, and to allow you to safely work on your copter with the props on.