Question about Visitors

I need clarification on visitors. I’m just starting to get into that portion of the game and some simply say “Not traveling,” so how do you know when they’ll visit? Some have a time frame like “Traveling next in fall.” So I can just wait until then, but how do you know for the ones that don’t specify? Also, for the ones that don’t say anything about traveling, if you make a satisfactory cabin for them, do you just wait and see if they show up?