sodastream

Hi, please could anyone assist. My Co2 Hambleton Bard cylinder has just expired and now are discontinued (used on 3 King Kegs). I am looking at buying a S30 adapter and a soda stream as a replacement method to inject Co2 in my barrel. Is this straight forward or do I require any other types of...

What exactly is it? and how do you do it, lets assume 20L cider, a 19L corny keg with sodastream co2