So, stick to it, and when you have read the whole book thoroughly, your knowledge of classical Chinese will be quite profound, and reading ancient books will be a cinch!
As a high school Chinese teacher, I once recommended this book to high school students. In the past, only books were recommended, not editions (publishing houses). After the students bought it, I read it. There are many versions and too many mistakes. I regret not recommending the publishing house version to them. Most books bought by students are made by semi-literates to cheat money, no matter what university press, education press or other press.
So this time, I solemnly recommend the two versions mentioned at the beginning, which should be helpful to you.