The filter is installed on the cold-water line just before the CUBE.
Mounting
Fix the filter head to a stable spot in the sink cabinet and plumb it in between the cold-water supply and the CUBE.
Fit the cartridge
Twist the new cartridge into the head with a quarter turn. Set the bypass valve to FILTER.
Flush
Run 5 to 10 litres of water until it flows clear; this removes dust and fine carbon from the cartridge.