There's one feature of SCART that may help you: the automatic "last one on gets the stage".
If the "box" has a remote with an "off" button, turn it off there (leaving the mains power on). That should mean the analogue aerial is still connected. Pick any analogue channel to watch.
Then power on the "box". If things are working right, the TV should switch to watching the SCART input. Then poke around with the remote for the box (don't touch the TV one) and see what you get. If you don't get any TV station, it may not be tuned in. If you can get a solid picture with any of the "functions" of the remote, then you're in with a chance.
There's probably a setup function, and that probably includes an automatic "tune and set up stations" facility. The rest is easy.
If turning the box on doesn't bring up the SCART input, then check that the SCART connectors are in the right sockets - I'd bet there are at least two on the "box" - one to go to the TV, and one for a VCR to feed though it. Try the other one to connect it to the TV (and then repeat the stuff above).
If none of that works, try unplugging the aerial from the "box" and connecting it direct to the TV. Unplug the mains from the "box" and see if the TV works OK. If it does, then the box isn't going anything at all and further research into the buttons on the TV remote may be called for - even (dare I say it?) fishing out the Fine Manual and reading same.