No show at all of doing it yourself. Once a new compressor is installed the next step is to pump the gas back in to the compressor & pipes. Unless you have a gas cylinder & pressure gauges etc you can't do it. Is the motor still running when turned on? If so, then it may of just lost the gas & needs a service company to come & regas it for you. Much cheaper than replacing the compressor as well. If motor is running, then turn it off until it has been gassed. The motor will overheat & then you will have to replace the motor as well.
Lincoln Appliance NZ, February 2009