There isn't much to say really, it's unskilled labor that doesn't have a lot of intricacies.
They bring you the dishes, you clean them and bring them back. Sometimes they won't bring them to you and will expect you to go fetch them.
Most places have a pretty nice commercial-grade dishwasher machine that cleans things 30 seconds max, you use the machine for things like utensils, plates, bowls, cups, basically anything small. You'll wash pots and pans by hand in a separate sink.
When you go in don't expect to just be washing dishes unless your restaurant is insanely busy. Most places will expect you to do various cleaning jobs on your down-time and at the end of the night, such as sweeping and mopping the floors, taking out the trash, organizing the cooler and the pantry, breaking down boxes, etc.
For the most part dishwashing is just mind-numbingly boring.
Also I hope you aren't worried about having pretty hands, because between handling chemicals all day, sorting and carying 160 degree plates and silverware, and steel wool eroding your fingernails down to the bed, they are going to look chewed up pretty fast.