Hi Keith.
Perhaps leave yourself three hours from starting to drop off your car…..there could be delays or lineups doing this part.
This also gives you time to use the bathrooms, get a snack, find your way around etc at the railway station; and not be rushing in an unfamiliar place.
Others may chime in and say it’s too long, but that’s what I would do if you have not used the trains before.
Buy your tram tickets from the little shop just inside the airport entrance doors , to the right as you enter.
The ticket machines on the platforms are busy and a bit confusing to work out.
Then exit, and the tram platforms are just to the left of the building.
Validate your tram tickets in the little machines on board to avoid fines from inspectors.
The machines are bright yellow, if I remember.
Get off the tram at the station…it’s to your left as you get off.
The stop is “Alamanni- Stazione SMN”.
Just about everyone will be getting off there.
There are steps to get up from street to station level.
The station is a very busy place….hang on to your personal stuff closely.
The only check before you board is a gate with an official checking train tickets right at the platforms so that only ticket holders can be on the platforms, so keep your passport and cards, etc tucked away safely….you don’t need them.
Keep an eye on the big indicator boards for your platform.
Know the number of your train, as it may not be terminating at Roma Termini station, but be going on to further south.
The board will list all the stops for your train number.
Sometimes the correct platforms are not shown until about 10-15 minutes before departure, then you can go through the gate.
Have a great trip!