From a Google search, I find that it is quoted from "Harry Potter and the Chamber of Secrets," and it is two sentences. Harry has been working hard in the garden, spreading manure, so his shoes must be dirty. Aunt Petunia finally calls him in, saying "Get in here! And walk on the newspaper." I can't find anything that clarifies it, but it seems pretty obvious. There must be a doorway from the garden into the kitchen, and, instead of a doormat, Aunt Petunia has put down an old newspaper. People entering the kitchen with dirty shoes are supposed to walk on the newspaper in order to keep the kitchen floor clean.

Without any further context, I would assume that the meaning is literal.