Actually, this mission is considerably shorter than others, or so it seems. Your first objective is to kill Union soldiers with your rifle on a hill to your left. There will be several enemies up there, so aim your shots carefully. After that is taken care of, you will move up towards a wagon with some debris around it, and will be attacked by some Union men. Kill them, then move up and take out any resistance. Your final objective is to move up to take out 4 cannon teams on top of a ridge. Once they are taken care of, you will be told to retreat, and, while killing anyone in the way, you will move back to your starting position and the mission will end.