Do you want to read a really entertaining book?

The Great Pianists, by Harold C. Shonberg

https://www.amazon.com/Great-Pianists-Mozart-Present/dp/0671...

You don't have to worry about reading the whole thing. Read through Bach and Mozart (and maybe Beethoven) to begin with. You'll get a feel for the historical background, and mention of their major pieces. Then, you go listen to the pieces.

I know these are pianists, but a good number of the great composers were some of the foremost pianists of their time.

Supplement a composer you've read about with a YouTube video or two, and their entry in Wikipedia, and you're off to a great start.

Anyway, that's one approach.