The dishwasher instruction manual will show exactly where to put the salt, but generally there's a screw cap in the bottom of the tub which you unscrew and then you can fill the salt container. It will take a lot of salt (maybe as much as a kilo!) and water will overflow from the container as you put the salt in.
Your dishwasher has a water softener built into it which softens the wash water. At the end of the wash cycle the salt is used to clean the resin in the softener unit so that it continues to function correctly.
NOTE: Tablets with added salt must not be used as a substitute for refilling the salt container.
Jeffers, January 2010
