To troubleshoot your central AC, start by checking the thermostat settings to ensure it's set to cooling mode and at the desired temperature. Next, verify that the circuit breakers and power switches for the AC unit are on. Inspect and clean or replace the air filters, as clogged filters can hinder airflow and cooling. Check the condenser unit outside to ensure it's not obstructed by debris or vegetation. If the AC is still not working, it may indicate a more significant issue, and it's best to contact a professional HVAC technician for a thorough diagnosis and repair.