Doe the home have a WiFi router? If yes, make sure Vera and your iPhone are connected to that router (wired or wireless) and within teh reach of that WiFi router you can control Vera from your iPhone. Even without connecting that router to the internet.
You will need to use a 3rd party app as the official Vera app most likely requires you to log in. Since you are on ios you can use HomeWave and there are a few others.