what train station should I use to connect to Hangzhou from Pudong airport

Well, it's not necessary for you to take a train.
At the airport, you can take the long-distance bus to get to Hangzhou directly.
The bus schedules are 8:40, 10:00, 11:00, 12:00, 13:00, 14:00, 15:00, 16:00, 17:00, 18:00, 19:00, 20:00 and 21:00. The duration is about 3 hours.