Read the book that came with it. Follow the instructions re: loading the trays, how much detergent to use & which setting to use. If you do all that they advise you to do and dishes are still not clean then contact the shop & have it checked. Either that or get rid of it and wash by hand like I do. Much easier and better result. Favourite saying of mine is " Dishwashers are for lazy people"
Lincoln Appliance NZ, October 2015