|Hi, Swamp Shadow, welcome to this place. You'll find a wide range of participants, from authors, historians, reenactors, National Park Service, museum guides, and just plain folks. Also there are a couple of other high-schoolers in here.
Some have studied the war for years, others, like me, have gotten interested only recently. There's so much to learn.
For an overall understanding of the Civil War, you might read Battle Cry of Freedom, by James McPherson. Many people consider it the best one-volume history. Then you can move on to topics that attract your interest.
You can look at military campaigns, the biographies of the soldiers, the history of a particular unit such as a regiment, the political situations on both sides, the social and economic factors. You can study how they fought, and why they fought.
Another way to learn about the war is to study the technological firsts:
Items such as carbon paper, tinfoil, and electric batteries were used, but I don't know if the Civil War was the first.
- first use of land and water mines (they were called torpedoes)
- first use of railroads to transport armies over long distances
- first use of balloons for aerial reconnaissance
- first use of photography to document events
- first use of photography to reproduce maps for quick distribution
- first use of ironclads
- first use of the revolving gun turret
- first use of repeating rifles
- first use of telegraphy in the field for instant communication