This is a large train station and an attractive building in its own right, as is often the case in Italy.
Everything is clearly signposted in Italian and English. Ticket office, self-service machines (not only for Trenitalia, the Italo company also has both ticket options), departure board, plenty of eateries, shops, etc.
Annoyingly the authorities have installed barriers before the platforms where you have to scan your ticket, and the barriers will only let you through a few minutes before your train leaves.