Which Metro should I take ?

I will be arriving Guangzhou South Station and need to get to Baiyun International Airport to catch a flight from China Southern Airline.
1. Which Metro line 2 or line 3 is more quicker ? Is it easy to get a Metro ticket ? How long does it take ?
2. Which terminal is China Southern Airline ? Please be specific (example Terminal 2, North or South Terminal)

Thanks
Ed