How to work a home thermostat?

I just set mt thermostat from heat to cool and put it at the lowest temp. But it is not that cool in my house. Its actually kinda hot. The air coming out of the vents is not cold its more warm\cool mix. Is there something wrong with the thermostat? Also there is a fan setting and a settin that says norm. What do those mean?How to work a home thermostat?There should be a switch to change over to ac if you have central air.You leave fan on normal for when the furnace kick on the fan will also.How to work a home thermostat?May be ac not working.