I arrived PVG at 5:25Pm . How can I get a train to Nanjing ?

You can take the airport shuttle bus line 1 from Pudong airport to Hongqiao airport, then walk to Hongqiao railway station and wait for the high speed train to Nanjing. The last high speed train departs at 20:10. You need to seize your time. If you miss it, you can take the last bullet train from Shanghai Hongqiao Train station to Nanjing at 21:25.