Originally Posted by JohnJ80

Here are the actual instructions on how it works and how you do it. You power meter needs to support the power meter profile under BTLE and/or ANT+. Fortunately virtually every current device does.

https://support.wahoofitness.com/hc/en-us/articles/115000369590-How-do-I-Calibrate-a-Power-Meter-with-the-ELEMNT-BOLT-