When you fasten the Ava around your wrist, there is a sensor light on the underside of the pod that should switch on upon contact with your skin.
This light should stay on as long as Ava is in contact with your skin and should still be on when you wake up in the morning.
If the underside green sensor light does not turn on upon coming into with your wrist, try sandwiching the sensor pod between two fingers, taking care to touch the black rectangular sensor to see if that will prompt the green light to turn on.
It’s possible that your Ava 2.0 may not vibrate immediately upon coming into contact with your wrist. Please note that it can take up to 5 mins until your bracelet vibrates to indicate that it has started recording data.