Honeywell RTH8580WF - Preset Energy-Saving Schedules

Align the thermostat to the wallplate and then snap into place.
10. Switch heating/cooling system ON
Switch power back to ON for your heating/cooling system at the breaker box or the system
switch.
11. Set date and time.
Touch s or t buttons to change displayed time and date.
Press and hold a button to quickly change a setting.