Pose Detection Joint Distance

Hi, is there any documentation on how to use Joint Distance Active State in Oculus/Interaction/Runtime/Scripts/PoseDetection

Looks like I can use it to create two hand poses. Looking for more details on how this works. 

Also would like to know if there are any documentations/guides on how all the other scripts under pose detection works. 

I have opened all the samples, not all of them are covered in the sample. 

Thank you.