What train to take to get the E train?

You can get from any train to any other train on the New York City subway system. You may have to make 2, 3 or possibly even 4 transfers, but you can get from any train to any other train without exiting the subway system.

Point being, this question does not have enough information to be answered. The answer depends upon what train you are starting out from.

So, please ask your question again, this time specifying a starting point: either an address or cross street, or a subway line, for example: "How do you get from Delancey Street and Ludlow Street to the E train?" or "How do you get from the D train to the E train?"