Hi Peppermint
We have used the Official Italian Railways Uk Agents Site, see below
Italian Railways - Official UK Site - Information on Italian Rail Tickets and Passes, timetable, maps and live bookings on the whole network at low prices
Be aware that Scalea is known on the railway system as Scalea-Santa Domenica Talao and putting in just Scalea is often not recognised.
On this site you can check times, and book & reserve seats up to 2months in advance.
For August travel I would advise if possible that you reserve your seat as trains get busy!
The tickets come in the post within a couple of days. You can also see if the train is direct or if you have to change, & the type of train ie regional (slow) or express
You can get a bus outside Naples airport terminal to the station, takes about 15mins cost around 4 euro, taxi quoted my wife and a couple of her pals 50 euro,
best wishes
john