Complex sentence: The British troops began to advance at the retreating Americans, however, the 200 troops of the 13th Continentals that Glover had stationed behind the stone wall stood up and fired at the British when there were only 30 yards away.
Split into simpler sentences: The British troops began to advance at the retreating Americans. However, the 200 troops of the 13th Continentals that Glover had stationed behind the stone wall stood up and fired at the British when there were only 30 yards away.