Kunming changshui airport to south railway station

Hi there
I arrive at changshui airport at 9:50 am and I need to book a train to Guangzhou from south railway station. I saw that I can take the metro all the way but I'm not sure how much time it will take me.. so I need to know how much time should I take between the arrival at the airport until the departure of the Guangzhou train...
Thanks in advance,
Idan