There are several things to do in this situation. First, you need to check the thermostat, replace the dirty filter, clear a clogged condensation drain, clear the compressor area and if all those methods don't work, call a technician.
Check the filter of your AC. Most of the common problem of air-conditioner is on the filter since it absorbs dust and it is prone to block the wind of your AC.
Make sure all the vents are open and the thermostat is adjusted correctly if your air conditioner starts up but does not blast out chilly air. Check the air filter if neither of these are the issue. You would not get air movement if it is blocked with dirt or other particles.
If your AC is not blowing air, check the thermostat, air filter, and circuit breaker. If these are not the problem, contact an HVAC professional for repair or maintenance.
Try cleaning your air conditioner's filter and the coils to see if improving the airflow fixes the problem. If there is ice buildup, you'll need to run the unit with just the fan in order to melt it off. If that doesn't get the unit blowing cold air again, it could be refrigerant levels are low