Complex sentence: He began his coaching career as an assistant coach for AZ and then NEC, having had a brief coaching stint in Australia with the Brisbane Roar, before coaching Jong FC Twente to a national title in the Dutch reserves league.
Split into simpler sentences: He began his coaching career as an assistant at AZ and then NEC. He had a brief coaching stint in Australia with the Brisbane Roar, before coaching Jong FC Twente to a national title in the Dutch reserves league.