Yep - that's where you do it, of course it gives you zero indication of if/when/etc it's connected or not so it's not a super useful function.Go to Apps > Software Updates. From there, you can choose your WiFi network.
Mine is connected to my wifi (in theory) but I still get that "-4" error every so often and it's just not updated. I don't have good cellular coverage where I live (especially At&t) but my wifi is quite good, and absolutely works where the truck is normally parked. Still won't update.
I'm somewhat hesitant to get the USB update as this should just work right... learning UConnect doesn't really do that (work right)