If it's for 12 June or later, wait for trains to show up. There's no rush. Trenitalia has just begun to publish its summer timetable on its own website and it takes a bit of time before it shows up elsewhere.

Booking Trenitalia day trains is cheaper via ÖBB using these steps (no booking fees).

If it's for a train before 12 June, which train is it? (origin, destination, date, departure time)

Hi

Thanks for your help. It’s not until August so I’ll keep checking. 
Tony

Even WHEN times for then are publihsed, it may not be possible to BOOK untill 3 month ahead of date. And again: there is no real need to rush on that specific day, plenty of treni with plenty of posti a sedere every day.