How to connect(For Bluetooth Version,ONLY to do this step at time FOR IPHONE 7/8,7/8+,X/XS/XR,XS-MAX) 

1. Plug in the earphones to your iPhone. 
2. Go to Settings > Bluetooth (turn on) > Select "Beat" 
3. If you want to link another iPhone, you must disconnect the Bluetooth link from the original iPhone first and plug the new iPhone then do the step 2 on the new iPhone.