If you'll permit me to drop a couple links, this is Hardee's Rifle and Infantry Tactics, the most common Confederate drill manual, and this is Casey's Infantry Tactics, its Union counterpart. These manuals cover infantry drill in detail from the individual to the battalion/regimental levels: everything from how to form the battalion for line of battle to how Private Snuffy is supposed to present arms. Manuals like these were incredibly important because the average Civil War volunteer officer received no formal training. Unless he was lucky enough to be a military academy graduate, he had the responsibility of first educating himself in tactics and drill, and then teaching his men. The performance of the company or regiment (brigadiers were appointed, not elected, and usually had more advanced experience) depended on how well drilled they were. This meant that, when it came officer electing time, you really wanted to vote for somebody who was literate and accustomed to responsibility. And if you look at the composition of these armies, that point is born out. Glatthaar's General's Lee's Army included significant statistical data on the Army of Northern Virginia. Among other things, it reveals that officers were both significantly better educated and considerably wealthier than the rank-and-file (education being heavily correlated with wealth in the pre-war South).