Int'l arrival into Guangzhou Baiyun on China Southern and transit to Xian . How do I go about this? Been advised the airport is quite big.

You need to follow these steps to make your transfer:
Flight Arrival - Inspection & Quarantine - Frontier Inspection - Baggage Claim - Customs Inspection - Transfer Procedure - Security Check - Waiting & Boarding.

The signs in the airport are clear, so you can easily make the transfer. I also heard that the passengers' of China Southern Airlines can enjoy a special service at the airport, but I am not sure. You may ask the flight attendant to consult more information.