Yokohama Station is absolutely huge. Numerous train and subway lines converge here but not quite all at the same point. Be sure to have a very clear meeting place designated(in advance!) if you plan to find someone here. Many of the train lines have exits that place you in far different places. Fortunately, the signage(Japanese, English, and to a lesser extent Chinese and Korean) is pretty good. There’s also an information booth for tourists(to Yokohama, not just to the station) on the main concourse. As Yokohama’s central train station, there’re tons and tons of shopping and dining options in the area – to the extent that the options might be overwhelming. Have fun!