This will save you time. The tokens are also good on city buses. The most important thing to know when you enter the subway station is which direction you want to travel. Normally, this is a choice between uptown or downtown, north or south. There are two types of trains - local and express.
Local trains stop at every station on the line while express trains stop only at the major stations.
If you have any difficulty, ask anyone in the station. New Yorkers love to give directions. The subways will take you to all parts of New York City, not just Manhattan. If you want to go to Yankee Stadium, take the subway. If you want the fastest way to the beach at Coney Island, take the subway.