I agree with Terry. It is completely counter-intuitive from a trip planning point of view, in my opinion. You cannot actually plan a trip with it. So I would consider it solely a navigation program.
All of the other similar programs (Mobile PC, Odyssey Navigator, Navmii) seem at least a little better if you want to do some trip planning. They will all let you create a route with multiple (waypoints, POIs, "stops", whatever you want to call them) along the way and then see the route onscreen and look at the directions.
I've been learning how the Itinerary works as we've worked through this, so you aren't alone.