How do you replace the air conditioning compressor in a 1996 hyundai's accent?

By law, this must be done by an ASE certified tech in an EPA certified shop which has the equipment to properly recover, store, and recycle refrigerant. Additionally, since removing the compressor opens up the AC system, the receiver-drier (if it's a Thermal Expansion Valve unit) or accumulator (if it's a Fixed Orifice Tube unit) will need to be replaced, as well.