Finding my great grandfather first

Isak Schefloe/Shoevlo/Schiefloe & finally in America - Sheffloe Born October 13 (or 18?), 1836, Steinkjer In the 1865 census as 30 years Left Stod for America in 1866 (he is one of 5 children born to parent John Olsen Schiefloe - born 1799 and mother Marta Pedersdatter - no DOB. Siblings are Ole, Baard, Petter, Andreas) Gr-grandmother: Baralina Aagaard Sheffloe born 1855 on Rovik Island unsure of date she left Norway Maternal Gr-gandfather: Hans Stephenson born October 21,1848 in Branbu Bertha Marie (sp?) Pederson born November 10, 1859 in Modum Can you point me in the some more directions for additional information about their emigration? Or in searching for local relatives from other siblings. I am very new to this but enjoy searching records on the internet. THANKS!