Can I please know what buses are available from Zhangjiagang to Wuxi. My destination is Xian

Hi,
I am an American citizen and having trouble finding the correct bus or bus station in Zhangjiagang. My place of destination is XA and so what is the best way to get there? I was thinking of taking a bus from Zhangjiagang to Wuxi and once I got to Wuxi to take a train to my destination. Please help because it's difficult just finding a site with the correct instructions.