If I make an reservation from home, how will I know what station to catch the train ?
Because you make the reservation for that station. On the schedule when you a routing, it indicates the station being used. And the ticket will indicate the station just like your airline ticket indicates which airport your are leaving from or landing.
I don't think I understand. Each station has a name. You catch the train at the station with the name for which you made the reservation.
I don't know any station's names, I'v been looking on raileurope.com it just ask for the region. I haven't found any specific train stations .
Rail Europe is the worst place in the world to get reservations. First, they add a huge surcharge (profit) for themselves. Second, they don't have a very good selektion. Try to find the cost of reservations on the national rail website for the train you want to ride. In Germany, there are almost no trains that require a reservation, and if they do, in most cases, it is just a nominally price seat reservation.
You need to spend some time with guide books as they will always indicate which train stations you need to use. Many cities have more than one station. Paris, for example, has six or seven.
Or, just let us know what you have planned. There's usually a few people on this website who are willing to walk you through, step-by-step. And forget about RailEurope, EUrail, etc. Use the websites of the various national rail companies, or the Deutsche Bahn website.
Now that we've convinced you NOT to use RailEurope, let me just say that RailEurope does sell reservations to towns (like Frankfurt, or Munich) not by regions. The only place they ask for any thing that looks like a region is when they ask what kind of a pass you have (eg Eurail France-Germany). On the home page, box on upper left, click "Book a Reservation for Your Pass. But don't book German Rail Reservations from RailEurope. For a 2nd class seat, they charge $12. You can book a reservation on the German Rail website for €4,50 ($6.44 at today's exch rate).
Use the Deutsche Bahn website to figure out your train schedule: http://bahn.hafas.de/bin/query.exe/en Here's some additional helpful info on the trains. Once you have determined your route, print off your schedule and take it with you. You can show these to the agent to buy your tickets. When looking at these schedules online, you can click on the arrow on the left to see all the stops that particular train will make. I like to print this off so I know what stop will happen before the one I want. It will also show any changes/transfers the train will make. Like you said, it is often times hard to figure out what station you want, say in Venice. So, ask us in another post. Someone will be able to help you.