First, find your water heater. It should be in your veranda or wherever your washing machine is. There should be a main valve switch on the pipe or pipes come out of it. If they are on the handles will be pointing the same direction as the pipe. Then go back to your thermostat. For now, set the timer to zero. The timer is for how long you want the floor heating to run.
Then try pressing the second button and see what happens. The way my system works is that when the button for the heating/water is pressed in, I only have hot water. When it is out or off, I have both hot water and floor heating. Other than that, look to see if there are and flashing lights. If there are that means that there is a problem with the heater. If not, then talk to your co-teacher.