Schedule of Guangzhou air shuttle bus Line 1

Dear Sir or Madam, I find divergent informations about the schedule of Line 1 shuttle bus from GZ Railway station to Baiyun Airport. I will live in Guangdong Baiyun City Hotel and will start at GZ railway station. Because I have to arrive the airport at 6:00am, it is important for me, to get the exact start times of the bus from Railway Station. Please, one more question. Where can I buy the ticket for the shuttle?

Thanks in advance
Roland