Start with the vernacular classical novels that are easy to understand, such as The Water Margin, The Journey to the West's The Scholars, The Flowers in the Mirror, Three Heroes and Five Righteousness, and then read The Romance of the Three Kingdoms. You can watch Strange Tales from a Lonely Studio after reading it. After reading the ancient prose, you can probably understand it. It is up to you to improve in the future. However, there are several points to note. First, don't read the abridged version. Second, don't look at the translated version. Third, if you don't understand, you can look it up in the dictionary, and you should look it up more. Only in this way can you make progress.
I'm reading an anthology of China's classical literature, and I'm talking about some texts in The Classic of Mountains and Seas, The Book of Songs, Shangshu, Laozi, The Analects of Confucius, Zhuangzi, Mencius, Mozi and Songs of the South. I suggest you look at some classic texts in these books.
If you are interested in ancient Chinese, our ancient Chinese teacher recommended us to read The View of Ancient Chinese.