Olaus Larsson Austad

I am trying to find more information about my great grandfather, Olaus Larsson Austad, as he was recorded in the 1865 census. He was born in 1856 near Hylla or Rora, North Trondelag county. He emmigrated to the US in 1882, and soon married Martha Kjerstan Hellem, who emmigrated w/him and came from the same area. I have no information about which ship they arrived on. They settled in Enderlin, Ransom Co., North Dakota. I'd very much appreciate any information! Thank you!