Hi, you should go to the Shanghai South Railway Station. you could search out the timely train schedule. A common hard-seat ticket it ok since the journey is just 2 or 3 hours. If you would like to leave early in the morning, it is smart to buy the ticket one day in advance. If you have enough time on the leaving day, it is ok to purchase the ticket when you arrive at the railway station. May 19 is not a weekend, so I think it is easy to get a ticket.