Things to see in Riomaggiore

The regional train that runs along the Sestri Levante (Levanto) - La Spezia Centrale line stops pretty frequently in all five of the Cinque Terre villages. Coming from Milano Centrale (Milan), you can buy a ticket that should connect you through one of the Genoa stations, with a change to the regional train. This journey should take around 3 hours.

There is a direct train from Firenze Santa Maria Novella (Florence) to La Spezia Centrale that makes frequent stops at most major stations along the way. The train from Pisa runs along this same line. Once again, you will need to connect to the regional train once you arrive at La Spezia Centrale. This journey should take around 2 1/2 hours.

On the regional train, there's a chance you might end up stopping in the middle of a tunnel. There should be a sign that says Riomaggiore somewhere in the tunnel. It might be a good idea to check with someone else on the train to see if you're in the right place. Once you get off the train, you'll need to head east on foot and you'll reach another tunnel with art on the walls that will lead you directly to the main street of Riomaggiore called Via Colombo (which will be on your left [the only way to turn]). If you continue straight, you'll immediately see the steps to the marina. This all should theoretically be easy to find, but if not, there should be someone at the tourist info office situated near the train tracks who will let you know how to get to where you need to be.