Train from Hong Kong to Guangzhou

We are travellig to Guangzhou on Mar 19, there is a 12 hr stpover in HK so we thought we would catch the train to Guangzhou instead of waiting for a flight. There will be 3 travelling, is catching the ride easy to do if you have not did in China before. Is it easy to get from the airport to the station, collect tickets and get the ride :)