I am a US citizen, living in Taiwan, wanting to run tours in Norway, China, Taiwan, and the U.S. Only me at first as tour leader for each tour, small tours of only 6-10 people. I am just wondering, where to begin with licensing, do I need it in all of these countries? Only one of them?

I'm just not getting started looking into this and finding it somewhat difficult to figure out where to begin, if anyone could point me to some generally relevant information that would be great too, thanks.