Complex sentence: From the landing the Nez Perce proceeded upstream on Cow Creek where they encountered a wagon train with more supplies which they also looted and burned and fought off an effort by 50 soldiers and civilian volunteers under Major Guido Igles to pursue them.
Split into simpler sentences: From the landing the Nez Perce proceeded upstream on Cow Creek where they encountered a wagon train with more supplies which they also looted and burned. They turned back an effort by 50 soldiers and civilian volunteers under Major Guido Igles to pursue them.