how to use a dishwasher :O?

hey guys this question will shock you all but I have never used a dishwasher before (parents always said no need for that) lols but I don't know where to put the powder or tablet... there is a lid that just stays open and will not close I don't know why maybe its broken? and then there is this other thing that's a circle and I can lift it off? I think im suppose to put something in there but I have no idea?? arrggh help pls lmao I have a simpson silencio 850.