Set up the NFC sticker by clicking "set up" below, and tapping the sticker to your phone. Then, pick the device you'd like ...

Set up the NFC sticker by clicking "set up" below, and tapping the sticker to your phone.

Then, pick the device you'd like to sign in to by tapping and holding the tile of a previously paired device, and selecting "Set as your NFC sign-in device".

Next time you'd like to sign in to this device, begin by tapping the NFC sticker.

Note:
To begin signing in while your phone is on the lock screen, be sure to switch on… in settings. Also, you can only enable NFC sign-in for one device.