Safety and simplicity are key. First, ensure the machine is unlocked and the carbonation lever is in the off position. To install a new cylinder, simply screw it clockwise into the threaded valve at the top of the machine. Hand-tighten it firmly—do not use tools, as over-tightening can damage the threads or the pinching valve. You will hear a brief hiss as the cylinder is pierced and the machine pressurizes. To remove an empty cylinder, unscrew it counterclockwise. It's a straightforward process designed for quick and easy changes.