No, not how to draw for dummies- how to DRAW DUMMIES.
Really anyone can learn to do this even if you can't draw worth a darn. As the examples below show all a dummy really need involve is simple shapes; circles and rectangles and such. The key is to re-create the desired pose for your concept art. Now if you can afford a cheap commercial artists dummy ($10 at WalMart) but if you can find a better one get that instead, Stickfas are even better! You can do many poses. Failing that grab a GI Joe action figure, you know, the ones that are all super-poseable (ooooooh) or get a spider-man toy- they always make his action figures very poseable.
If you have no toys and no money for toys then make a stick man out of wire- since you will be using it for sculpting you might as well make it to scale too- make the arms a proper length- the legs the whole bit. If you can get some green stuff and bulk out the separate body parts a bit. Basically you are making a dolly- a blank armature but instead of using it for sculpture you are going to use it to gauge poses. It can also serve as a size guide for all further armatures you create so they are of similar size. Here is the key- pose your dummy into a pose that you yourself can re-create. Chances are if your foot won’t bend a certain way then your dummy shouldn’t be posed that way The key is that you want the figure to convey something. Think "what does it look like he's doing?" Chances are a freaky hunchback dummy that looks like he's crapping himself will sculpt into a freaky hunchback figure that looks like he's crapping himself. When you have the desired pose with your dummy draw a stick figure that corresponds to the dummy. Again ask what the stick figure is 'doing'. Overtop of this stick figure add balls and rectangles. Here's the loose rule: If it bends in anyway it gets a ball, otherwise it gets a rectangle.
I find it useful to have a collection of various poses sketched out long before any project as they are easy to recreate when you already have one to work from. So start your 'dummy' collection!