No need to use a train which is not conevenient. When you arrive at Baiyun Airport, please take the shuttle bus Line 1 to reach Guangzhou Railway Station. Here, you could find the Provincial Bus Station of Guangzhou to the west of the railway station. At this bus station, there are frequent buses departing to Humen about every 20 minutes. The bus terminal is at the Yongan Bus Station, Humen, where is the Huanghe Wholesale Market is just located.