Q: How do I unlock the schedule in the app on the SQ610 / SQ610RF?

The only accounts that cannot edit schedules are invited Guest accounts. Every other user level can edit schedules in the thermostat's settings, under Schedule.

For the thermostat to follow the schedule, change the thermostat mode from Permanent Hold (hand symbol) or Standby (power symbol) to Follow Schedule (A), using the symbol found next to the temperature dial.