I've been hitting the "not a person" button in the lower right corner. They should have a tutorial for each of the 50 census tasks, all I find is a video on using the app but little instruction on proper protocols to be implied (or at least I've not been able to find them). An old saying the the data processing field was "Garbage in, Garbage out".
The FAQ says -
"How do I handle notes that have been indexed as names—for example, “Vacant” or “No one is at home”?