How do I set up a Black and Decker steamer to cook dumplings?

I have a used steamer that didn't come with instructions, and it is sort of confusing to look at. It has three baskets, one with a central hole that fits over the heating unit and has a mesh filter on it. It also has a large plastic vented bowl and then a small rice bowl that doesn't seem to fit anywhere. It is much smaller than the other layers. Then there is a top that has 4 vent holes and only fits over the large plastic vented bowl (vegetable steamer?). I don't want to burn up the unit, and I would like to cook bean dumplings in it. Since I've never used one of these for anything (even rice), I am at a loss. I know where the water goes (in the bottom where the heating unit is), but I don't know if all of the other units must be attached or not, nor do I know where to place the dumplings to cook them. Any suggestions? I can't find any instructions at all beyond very general ones. Thanks!