Jj Daniels you really should get those pressure properly adjust by someone in the BioMed field or rep for this device. Speak with your healthcare provider about that.
For educational purpose, there should be a small door on the bottom right. If you remove that, there should be a slot that says "Pressure" You would need a screwdriver to adjust it. There are no preset pressures and you would need a manometer to get the proper pressures. Again, have your healthcare provider assist you with that.