Complex sentence: They arrived at Hay on 7 September 1940 in four trains from Sydney and were interned in Camps 7 and 8 (located near the Hay showground) under the guard of the 16th Garrison Battalion of the Australian Army.
Split into simpler sentences: They arrived at Hay on 7 September 1940 by four trains from Sydney. They were interned in Camps 7 and 8 (located near the Hay showground) under the guard of the 16th Garrison Battalion of the Australian Army.