Hello

I will be in Italy in Late May and I am trying to organise my itinerary.

What is the best order to visit these places via train:

Venice (2)
Cinque Terre (2)
Florence (3)
Assi (1)
Rome (4)

Look forward to you thoughts

What do the numbers mean?

I assume they're the number of days s/he plans to spend there.

It depends whether you're flying into and out of the same airport or doing an open jaw, and it also depends on which airport(s), but it should be easy to figure out on a map.

Try to fly into VCE and home from FCO.
I would do this:
Venice--3
Florence --3[ to include day trip to Assisi]
CT--2
Rome 4

Good luck !

I will arrive into Vencie by train and I depart from Rome. Yes the numbers reprsent nigths at each location.

Bob's got it about right, but with only twelve days, you are spreading yourself too thinly.

Miss out CT, as it is a wild lunge to the left and do only Venice, Florence and Rome. There are a number of other posts on here at this time on this subject and a three centre plan looks about the best way to go.

Or do your Assisi daytip from Rome. If you catch the 7:52, it's 2 hours non-stop, shorter than the time from Florence. In this case drop a day from Florence and add it to Rome.