Hello Helene
The full schedule is out until June 10th.
As of March 1st the trainline has started to release most of their high speed Freccia routes from June 11th until August 5th with the exception of some dates.
Typically train tickets are released about 60-120 days prior to travel.
Regional train schedules are released until the end of May with those being uploaded closer to travel dates.
To look at a full schedule of your route, you may put a pretend travel date such as May 1st to assist in planning your route/train.
Summer schedule should be released around mid April/May for August 6th onwards.