Houw to go to Tianjin South Railway Station from TJ Convention Exhibition Center?

I am in TJ town (Todays International Hotel) No.2 Road Xingang Tanggu and want to catch a subway train to the South Railway Station where I want to connect by Bullet train to Shanghai. I needto know if I catch a subway train from TJ Convention Exhibition Center Station where am I supposed to drop to be able to catch the bullet train at Tianjin South Railway station?