Much like choosing the color for your new Model A Ford, people joining a military reenactment unit can chose any rank they want, so long as the rank is private. Other ranks are awarded by the Command Group based on an established set of criteria.
Confederate
Encampment
Many reenactors will choose an impression during a reenactment. Military reenactors will choose infantry, artillery, cavalry, or medical, and some will choose a civilian impression. While doing their “impression” many will do a first-person impression.