The following introduction was written by John Renfroe and published here: Learning Classical Chinese is for everyone (no, seriously!). The article contains an introduction to classical Chinese, as well as many recommendations for books to use, including this one.
At the beginning, I used Michael Fuller’s excellent textbook, An Introduction to Literary Chinese. This book starts out by covering the basic syntax of Classical Chinese, then guides you through progressively more challenging “intermediate” texts.
Along the way, you get experience with using dictionaries of Classical Chinese, as well as classical commentary and other resources. After that, you read more difficult texts, progressing from classical texts like Mencius (Mèngzǐ 孟子) to Tang and Song writing by Hán Yù 韓愈/韩愈 and Sū Shì 蘇軾/苏轼. It’s a wonderful textbook, and it’s very popular, so if you get stuck, you can ask for help online (there’s a fairly active Classical Chinese subreddit, for example).
The book is full of exercises beyond just the reading selections, and I highly recommend completing the exercises as much as possible. Some of the exercises require access to a library, so they may not be practical unless you’re near a library with a reasonable Chinese collection, but most of them should be doable.