Hi.. Im new here With questions :)

Hi :) Maybe someone can help me out here.. Ive been doing my family tree for a while now and have just now gotten to searching past family in Norway. The 2 people i am searching out are my great grandparents, Halvor Halvorson (changed to Halvor Serikstad) And his wife Rense Bendikte (maiden name Kohn) Serikstad. I dont know if she took on the Halvorson name and then became a serikstad for the trip to NYC or what. Im trying to find their marrage certificate to see if it has more info for me to go on.. but i dont know where to search for that. (I think they migrated to Stavanger and adopted the serikstad name there from a farm(?) because thats the only place i see the name as beeing so popular in my searches, lol then went to Farsund before he came to america (on his Ellis island file it shows Rense as living in farsund at the time) The records i find are way too old to even have them in there. Halvor is listed as being born in Skien 1897(cant find anythign for there) I know there are a million reasons for the name changes, moving to other farms, hiding from "dues" etc.. But something has to be out there.. Im kinda getting to the point of agrivation and i didnt want that to happen b/c this is supposed to be fun :p So maybe someone can help me a little bit ? Sorry if that is a big confusing mess... thats just how my brain is right now lol Thanks for looking :) ~Dawn