Complex sentence: He reportedly hid out in the forests surrounding Anderson, and preyed upon the Union soldiers stationed nearby, using guerrilla warfare tactics, which he would have been familiar with from his experience as a scout during the American Civil War.
Split into simpler sentences: He reportedly hid out in the forests surrounding Anderson, and preyed upon the Union soldiers stationed nearby. Manse used guerrilla warfare tactics, which he would have been familiar with from his experience as a scout during the American Civil War.