I never saw the option offered on mine for face unlock. I want it. Where do I find it?
Settings-Security &Location-Smart Lock (pin)-Trusted Face.
As best as I can tell, once you register your face Face Unlock is automatically turned on. If you hit the power button while the screen is pointed towards your face, the phone will unlock. You can then just slide on the lock screen to get to your home screen. I do not see a way to trigger Face Unlock from the lock screen other than by powering on.