@Shannon692 Yes, I think that phrase must be generated by Airbnb, as I see it in all entire place listings.
But you should make it clear in your ad that the basement level is not included in the rental, beyond telling them the main floor is for their use.
You are remiss in not making it clear that there may be someone else staying in the separate downstairs unit. I'd be upset, too, if I thought I'd have privacy, only to find out someone else was staying in another part of the house and would be coming and going and perhaps sharing the yard.