how frequent does the metro line 3 runs from Baiyun airport to Guangzhou east station?

10-15min frequency (12rmb) to Guanzhou east railway station. From there you can buy the tickets going to dongguan. Buy the 1st class tickets and after buying just follow the crowd when ready to board the train. For a first timer it be a little bit hard just ask around for directions because the area is big and can be confusing at times.