Welcome to the forum. I'm guessing when you mention Sky+ you mean your Sky+ bix is wired up to your satellite dish?
Unfortunately satellite transmissions and Freeview transmissions are two completely different systems, you won't be able to plug the satellite cable into the Smart Box or convert the satellite feeds to work with the Smart Box.
You'll either need an external rooftop Freeview aerial or a portable indoor Freeview 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.
As Andy says the Sky and Freeview systems are very different and you wont be able to use the Sky cable on your smart box.
However if it helps I have struggled for a long time with Freeview reception in my bedroom as there is no access to the outside aerial in there,
I recently invested in the following indoor aerial which gives me full reception of every Freeview channel including all the HD ones.
I hope it helps you or someone else reading these forums.
Sorry to jump in on this thread, I've looked at others and can't see a definitive answer to my problem:
Switched from Sky+ hd box. I have no outside aerial at all and previous ones I bought didn't pick up anything as it's such a low signal area. My son has freesat in his room and that's hooked up (properly) to the sat dish. I see that the freeview signal is different to the sky one, so I take it the freesat one is the same as the sky one? I was hoping there was an adaptor I could plug the sky leads into, to convert it into an aerial one.. but guessing by other threads that isn't possible. That link to the wsky aerial thing could be a solution but don't want to waste time buying the wrong things.
If I don't have an outside aerial and the inside ones aren't an option either, how do I get freeview via the nowtv box please? Thanks.
Welcome to the forum. Yep unfortunately Freesat is the same situation as Sky, it can't be converted to a Freeview signal. If Freeview aerials are also out of the question then I'm afraid you won't be able to set up the NOW TV Smart Box to receive Freeview transmissions (although all the other apps on the box including BBC iPlayer, ITV Hub etc will all work as they stream via the Internet) and your best bet is to keep watching via Freesat.