Yeah, Patti, I can see where it would be difficult to get your head around, coming from another pump system! The essentials are all pretty much the same, it's just the division of labour that's different.
The pod is basically a self-contained reservoir, pump, inserter, and infusion set all in one. So it does all the mechanical stuff of actually getting the insulin into you, but it's basically "dumb" - it doesn't know what to do without being told.*
The handset is the brains of the operation, stores all your settings and does the button-pushy stuff and the messages on screen and whatnot, and sends commands to the pod as needed (when you change settings or deliver a bolus). So it's like if you took all the mechanical parts out of a tubed pump and just left the computery bits.
*The pods "remember" your current basal settings once the handset sends them - so after you first activate the pod it gets told all your current programming, or, if you make any changes to your basals or stick on a temp basal, after that command is sent - so it isn't as if the handset is sending a command every 5 minutes: "give this much basal now". But other than that, the pod doesn't "know" anything else without being told.