Soak the stone fixer for 10 minutes and the medium/fine stone in water for the appropriate amount of time.
Use the stone fixer on the stone's edges first to take off the corners/edges of the stone to avoid accidentally chipping knives.
Start to sand off the top of the stone with a back-and-forth motion>
Remove enough material to flatten the surface of the stone.
If the stone fixer is used regularly after sharpening, it will take a shorter time to level the stone each time.