How can I go to Guangzhou from macau?

Well, you can pass the custom from Gongbei Port and then walk to Zhuhai Railway Station.
There are many trains that can take you to Guangzhou South Railway Station. The duration is 1 to 1.5 hours.
The train schedules are from 07:00 to 22:45.
And the fare of first class seat is CNY90 and second class seat is CNY70.