You might be interested in the Book list linked in the side bar!

Here is the section on the ACW. https://www.reddit.com/r/AskHistorians/wiki/books/americas#wiki_civil_war.2Freconstruction_era

In particular as a true starting point I would echo what is noted, Battle Cry of Freedom by McPherson remains probably the best 1 volume history of the war geared towards a more general audience.

It touches on all areas of the conflict, not just the fighting and political history, but the social, religious, and cultural conflict it brought to a head.

So a good place to start to ground yourself before looking at what you might want to learn more about from there!