READ THE FAMILY UPSTAIRS FIRST!!
Advertised as a "standalone sequel," but it's sooo confusing if you haven't read the first one. I read over half of the book before reading the family upstairs (there was a wait at my library for that one but not this one), and I was so lost. I reread this one after reading the family upstairs and it was wayyy less confusing. I definitely would recommend reading the first book first despite this being marketed as standalone. I guess it technically makes sense on its own but it makes way more sense and is more enjoyable as a sequel.