Using DB Navigator is as simple as entering the departure and destination cities. In a few seconds you'll have the shortest itinerary available and, even better, can take a peek at all the alternatives to see if any of them suit you better.
A very interesting thing about DB Navigator is that it shows you all the information related to the train you're about to take. For instance, if a train only has available seats in first class, it shows you that. Likewise, you can get info on the services the train offers: cafeteria, TV, silent cars, etc.
DB Navigator is an excellent app for all those travelers who take trains regularly ... especially those who take trains in Germany.