How Apple Pay Works on the Apple Watch

— -- The Apple Watch is meant to be a lot of things to the person who wears it. Chief among those roles are personal assistant, concierge, health coach and wallet.

When Apple's flagship wearable device gets strapped onto the wrists of the first customers, beginning on Friday, they'll have the option to turn their watches into payment devices.

Setting up the Apple Watch requires users to open the Apple Watch app on their iPhone and choose the "Passbook & Apple Pay" option. From there, they can capture as many cards as they want to load -- either manually or via camera.

For those who have used Apple Pay on their iPhone 6 or iPhone 6 Plus, the process for paying with the Apple Watch comes with a few quick changes.

Instead of working with Touch ID, watch users can double click the side button, choose the card they want to use and then hold the face of the device up to the contactless reader at any store that accepts Apple Pay.

A subtle pulse and a tone will signal the transaction has been completed.