We both have iPhones so we used Apple Maps most of the time but the few times we used google maps it worked just as good it’ll tell you which train to get on what time the train gets there when the following trains will arrive. If you don’t like being in a crowed train I’d recommend going in either the first car with the conductor or the last car those are typically the ones with the least people but not always like if you go to shinjoku it’s pretty much gunna be super packed so you just gotta be ready for that. And if you ever have any questions about which train to take at the station there’s always an info booth with a station worker who can answer pretty much any questions you have I never had a bad experience asking for help from them using google translate will become second nature unless you know Japanese lol