Complex sentence: He attended school at Cheltenham College, studied at the Royal Military College, Sandhurst from 1878, and was commissioned into the 42nd foot (Royal Highlanders) in 1879.
Split into simpler sentences: He attended school at Cheltenham and went on to study at the Royal Military College, Sandhurst in 1878. He was commissioned into the 42nd foot (Royal Highlanders) in 1879.