How do I make payment in stores with an Apple watch?
Pay with Apple Watch
-To use your default card, double-click the side button and hold the display of your Apple Watch within a few centimetres of the contactless reader.
-Wait until you feel a gentle tap.
When you strap your Apple Watch to your wrist you will be prompted to enter the device passcode. This will enable Apple Pay. If the Apple Watch is removed from your wrist, so skin contact is lost, Wrist Detect detects that skin contact has been lost and Apple Pay and the NFC feature are deactivated.