The set temperature in your room is 21 degree Celsius. With the terminal as displayed in the picture you are able to change that temperature either +3 degrees, or -3 degrees.
The best way to control your temperature is to up (^) the fan button until you will reach a fan symbol with ‘A’. this means Automatic, and will automatically set the best fan mode on how to keep your desired temperature.
If you want to shut off the system you press down the fan button until you reach the fan symbol with ‘0’, this will reach the minimum mode of the climate control. In this mode there will still be a fresh air supply, but there won’t be any temperature regulation (both heating nor cooling).