Hi, I need to book a train from Hong Kong to Guilin

what is the best route for this and where am I able to pick up my tickets for this trip once I purchase them?

I will be in HK for 5 days before traveling to Guilin and would like to have my Visa and all my train tickets secured before leaving HK for Guilin and the rest of my trip through Mainland China.

Any advice would be much appreciated. Thank you!