An S with a jug above the star means you need to add salt if you remove the bottom tray you will find to the left hand side a kind of knob you can open using your hands, open this and fill dish washer salt, Not table salt. Normally a bag would do. Close it and the sign will be gone on the next wash. Please note adjust the dispenser to your hardness of your water..
Leigh South Africa, November 2012