Depends on your budget, but there are many possible methods, if you don't want to hire an artist.
Google Sketch-Up has a free version which is good enough to create overhead plots for the Dircgtor and camera op as well as compose actual frames with camera angles, even animations, with people and key objects in them, and this works very fast.
For more photorealism, there's DAZ Poser, creates all kinds of people and there's a large catalog of object, motion filess and environments so you can build your scenes any way you need. Takes a bit more skill and time to work with.
There's an actual storyboarding app or two out there, the names escape me, but they work from a drag and drop template of people and shot types. I'd looked into them once but considered them pricy versus Google Sketch-up.