Complex sentence: Two Carabineros, Soto and Villagrán, were ordered to bring the horses and the other four men prepared their return as, at 16:40, they were surrounded by approximately 90 Argentine Gendarmes.
Split into simpler sentences: Two Carabineros, Soto and Villagrán, were ordered to bring the horses and the other four men prepared their return. At 16:40 they were surrounded by approximately 90 Argentine Gendarmes.