They seem to be assigning U.S. first arrivals/ and or surnames to certain groups and ethnic backgrounds. The challenge with this is that I am not sure it is that clear. Those ancient persons did not take the test and were certainly complex in their own heritage. Both the Brits and Scandinavia had mariners. The women may have stayed in one location but their names changed so trying to determine a heritage by surname or locations seems challenging. And we know the ones first into the U.S. were most likely to be the ones who traveled since they came here.
It makes sense to me that a certain surname or location may be more likely to be a certain ethnicity but should this be assumed or assumed for particular individuals. Also they seem to be assigning certain points of origin to different groups. I just don't see how it can be determined that a people living in proximity to each other could be so finely separated in ethnicity? And then add that to the fact that many in those countries were made up of many mariners and traveled both locally and more distantly. Even the royal families intermarried across nations and had ties to what are now considered other areas.