First you have to create a new Nintendo account, the Nintendo account I had from a long time ago that I would use back when club nintendo sent physical rewards can't be used, everyone's gotta start fresh.
After you do that if you want you can link your NintendoID if you have one from the WiiU/3DS, but I think at the end of the day you need to exchange a brand new 12 digit friend code.
Ya I don't have a Switch either. That's most definitely not because I don't want one, because I'm definitely getting one. I just wanted to make sure I actually completed everything on my goals list for this year, and I knew that if I got a Switch and Zelda, I'd be playing nothing but Zelda for quite awhile.