Take line going West and use the middle wagons and be aware when the conductor announce Jamaica Stop
5th from rear of train.
The one which is going towards penn station.
4th car from the east end of the train should place you right by the escalator at Jamaica station. Head up to the main elevators that will take you to street level and the lower subway level. Go to subway level swipe your metro and take the escalator down two levels to the J line. To the right of the escalator once you get to the bottom is the Manhattan bound line.
The one going west
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