Using a cream charger is simple: fill your dispenser with heavy cream, attach the charger

https://wiki-quicky.win/index.php/Whipping_Up_Creativity:_Artistic_Applications_for_N2O_Whipper_Cream_Chargers

Using a cream charger is simple: fill your dispenser with heavy cream, attach the charger, and give it a few shakes for perfectly whipped results in seconds.