Complex sentence: Terry gave the first indication that he was a white supremacist when he wrote and privately published "The Shadow", which dealt with his obsessions against Chinese and East Asian immigration to New Zealand to work the goldfields, or in horticulture or small business ventures.
Split into simpler sentences: Terry gave the first indication that he was a white supremacist when he wrote and privately published "The Shadow". This text dealt with his obsessions against Chinese and East Asian immigration to New Zealand to work the goldfields, or in horticulture or small business ventures.