Complex sentence: Hickinlooper served through the Atlanta campaign as an engineer with distinguished honor and participated in the march to the sea, and in the campaigns of the Carolinas, and was indorsed for brigadier general by General William Sherman, Oliver O. Howard and Ulysses S. Grant.
Split into simpler sentences: Hickinlooper served through the Atlanta campaign as an engineer with distinguished honor and participated in the march to the sea, and march through the Carolinas. He was indorsed for brigadier general by General William Sherman, Oliver O. Howard and Ulysses S. Grant.