If you want to learn some quick philosophy, but don't like hundreds of thousands of words of history books, you can read the Four Books and Five Classics, Caigen Tan, or the works of Zhu, Zhu and Zhu.
If the time is too short, choose some family instructions of Kangxi or Zeng Guofan's letters, which are both old and easy to understand and practical.
Hundreds of articles in the Spring and Autumn Period are very good. Zhuangzi's prose and Laozi's moral classics are short and pithy.
As a national study, Confucius is still the most basic. There are almost a dozen books about Confucius and Mencius and his descendants.
If you are interested, you can also look at the Book of Changes and so on. But it's good to scrutinize it repeatedly.
Contact with ancient Chinese, you can first find some books with notes to read.