How I can get the ticket if I buy online?

I have plan to travel in china, and my plan is Macau Zhuhai Guangzhou Shenzhen and Hongkong

Please recommend me about how can I go to Guangzhou from ZH. I would like to go Guangzhou by hi-speed train, and how I can get the ticket train at ZH train station.

regard,
Voravalun S.