Complex sentence: In early 1943, the 2/15th returned to Australia and after being re-organised and re-trained for jungle warfare, it took part in campaigns against the Japanese in New Guinea in 1943--44 and Borneo in 1945, before being disbanded in 1946.
Split into simpler sentences: In early 1943, the 2/15th returned to Australia and was re-organised and re-trained for jungle warfare. It took part in campaigns against the Japanese in New Guinea in 1943--44 and Borneo in 1945, before being disbanded in 1946.