Make Oneself At Home Meaning

(idiomatic) To make oneself comfortable as if one were in one's own home.

Example: 2011, David Almond, The True Tale of the Monster Billy Dean, Candlewick Press (2014), ISBN 0763663093, page 121:
  â€œWelcum to McCaufreys, Billy Dean” he says. “Make yorself at home & hav a pie.”