Can i do my own a/c in my 1999 buick regal ls it’s r134a can anyone walk me thru it and what will i need?

You'll need a hose kit. Usually available at auto parts stores. It is basically just a hose with one end fitting the can and the other the inlet on the automobile. You'll have to look where the lines go from the compressor to the firewall area of the automobile. There shoudl be a cap on what looks like a bicycle valve. You'll need a gauge to determine how much is in it (again, at the autoparts store). The main thing to know it to connect the can to the LOW pressure line, otherwise it could blow up in your face. This is typically the larger diameter line. It might be good to look at a Haynes or Chilton manual for your type of automobile.