Erinz on Family Tree Circles

I am just starting out researching my fathers father. My dad was adopted by his stepdad and took his name on. He never had contact with his biological father after his parents divorced in 1942. So I have no knowledge of my grandfather or his family.
His name was Jack Edmond Kitching and he married my grandmother Thelma Reece in 1937. They had two sons together Neville and Darryl. Then divorced in 1942.
Jack Was born in Nelson New Zealand.