Classical Chinese is very difficult to learn. It has very few in any grammatical rules, uses some archaic words and phrases, is very condensed, and contains ending particles that are no longer in use (for example 云, which in Classical Chinese means "to say" but is rarely used today for that meaning). I'm reading the Ming Shilu, the Seonjo Sillok, and the Ming Shi Ji Shi Ben Mo, which are all written in Classical Chinese, right now for research and I would say that if you can read Chinese, most of the times you will get a basic idea of what they are talking about.
There are books available in the research library where I am that helps with the reading of Classical Chinese. I suggest you go to a university library and ask the librarian for help. This website here
[click] is a good source for learning Classical Chinese. It explains Classical Chinese in detail and contains some English translations of Classical Chinese texts.
Also, this website
[click] (it's in Chinese) contains documents written in Classical Chinese with modern Chinese translation below. You can use it to see how Classical Chinese works.
Hope that helps!