You have central heat/air.  Be sure the thermostat is set correctly and the unit has a clean filter.  Free filters can be obtained at the JSM office.  You should check your filter regularly to ensure maximum efficiency.  Set thermostat on COOL and fan on AUTO.  Be sure to allow ample time for the unit to cool your apartment.  The air conditioner should only be used when outside temperatures are above 60F.  Operating the a/c when outside temperatures are lower than 60F can cause the air conditioner unit to freeze up, possibly damaging the unit.