Long-distance bus or train to Chengdu

I arrive at Jiangbei International Airport at 04:45 AM, and wish to travel to CD during the morning.
I am happy to travel by bus or train depending on convenience.

I understand that the long distance bus centre sits between domestic terminals T2A and T2B. Can I book and travel to Chengdu from this centre, and is the bus centre close to the international terminal (T1)

Regards
Ray