How to learn to master ancient Chinese for help?

Read ancient books, recite many famous articles, and try to write in classical Chinese.

I suggest you read the classics of Chinese studies, such as the Thirteen Confucian Classics. Introductory books can be 300 Tang poems, 300 Song ci poems, 300 Yuan songs, melody enlightenment, ancient prose, strange stories from a strange studio, new stories from the world and so on.