Is air conditioner installation a DIY project

ice usually means either your air handler isn't pushing enough air across the coil, or your system is out of refrigerant.

so first step is to set the cool/off switch to off. then set your fan switch to on. if the air handler fan does not turn on, then you have a problem with your air handler or thermostat. possibly cheap. possibly something you can fix yourself.

otherwise, you probably have a problem with refrigerant (which should not deplete, and if it does then you have a leak somewhere) or your compressor. in either case, you should leave your system off to avoid damaging your compressor until someone can come out and look at it.

You are missing something. Either you have not found the correct breaker yet, or the breaker is not inside the breaker panel for your house.

Walk through each breaker in the breaker planel for your house. You could have a mislabled breaker. (The breaker you are looking for is likely a two-pole 240V breaker, maybe 30 amps or better.)

Since this is a central cooling unit, it might be powered from its own breaker box. Follow the electrical supply wires (cable) back from the unit. Where does it go? You might find another breaker box dedicated to the cooling unit alone. There might also be a breaker in your meter box protecting the unit in addition to the main breaker for your house.