Indeed, it is the end. It’s a terminal.
If you want to get into the city, you need to go downstairs and hop on a PATH train, which is a subway service. One line goes to the World Trade center and the other goes to Herald Square (mid town Manhattan) with various stops along the way in both directions.
You can also take a ferry, too.
Damn, that’s a helluva commute, depending on where one is coming from