I have one that I use with my 7 gal chronical and unitank. First, throughly sanitize it. Clean and sanitize all the stainless parts and boil the oxygenation stone in water for 15 mins on brew day. Dump it in starsan to cool until it’s needed. I fill my fermenters from the bottom (yeast dump port) so I attach the inline oxygenation kit to that.
After I fill my fermenter, I set the regulator to the appropriate flow rate and time the O2 injection. Make sure you have your blowoff hose open and in starsan so you don’t pressurize the fermenter with pure O2!