IS there something special you need to do to move them from the campsite to the cabin?

I'm at level 74, just got there this morning and still have NO idea how to do this?!

ANY help would be appreciated.

Have you unlocked the cabin?

YES!! I had it unlocked and the bottom floor is filled, but haven't put any items in top floor yet, MAYBE
that's the problem. I'm at level 76 now. I'm unable to play a lot, due to the fact that I'm still able to work at
my job, we are listed as an essential business due to the fact we package organic eggs where my son and I work.

ANY help would be appreciated.

OKAY, so now I have the top floor decorated and I still don't know how to get the villagers to visit the Cabin!!!

Use the whistle shown at the top left corner

Didn't see ANY whistle, but the GREAT news is I figured it out and now have 8 more HAPPY campers at the cabin.
It turns out that you need to be at the Cabin, then click on the animal icon in the upper left corner, then a list of possible campers appears.