@Anonymous User
Welcome to the forum. Unfortunately Virgin and Freeview transmissions are two completely different systems, you won't be able to plug the Virgin cable into the Smart Box or convert the to work with the Smart Box.
You'll either need an external aerial or a portable indoor aerial to take advantage of the Freeview tuner in the box, although the NOW TV app and other catch-up apps from BBC, ITV etc on the Smart Box all work via your Internet connection so will still work even if you don't connect an aerial to it.
