How to use?

I have just moved into this property and i dont have any paper work regarding this thermostat ........and i dont know the number on it...All i know it has a moon sun dark blocks that look like bricks and a arrow at the bottom plus the time and temperture clock...I need to know how to set it to come on twice a day,I have the paper works for the boiler and that is ok....Just this siemens thermostat