"Well, this machine is the oxygen concentrater. You place it near your bed but not where you will trip over it. Now we need  the hose which connects here on the machine and travels to your bed like so. Next goes the hose for your face. Now adjust the air flow to the specifications.... You need 2.0 liters. So to turn it on here and adjust the flow of air with this knob..... Test it out, dear and see how that feels." Nanny Bessy spoke.