How to clean the dishwasher
Once a week, wipe the interior seals with a damp cloth and wipe the outside as it needs it. Clean the filters regularly - at least once a week. Once a month remove the filter basket and wash in hot soapy water.
To descale a dishwasher: Proprietary dishwasher cleaners will remove soap scum and limescale. They normaly consist of plastic bottle of detergent, which you up-end in the cutlery basket before running a full cycle with the machine empty. They are extremly efficient and leave the machine looking and smelling fresh and clean.
A cheaper alternative is to place a cup of white vinegar in the lower basket and run the machine. Also you can fill the powder dispenser with citric acid and run the full cycle with the machine empty.