train booking

I'd like to book the train Nanjing- Qingdao for the date 25 july. I don't know if is too early, how far in advance you can book the train. I already book the hostel in nanjing, then it's possible delivery the ticket to the hostel. After that i'm planning my itinerary in China and need to book other train, but I don't know if it's possible submit more than one reservation on one time
Thank you for your attention
Marcello Colacicchi