You can then set a route for the Droid to patrol around the house. The astromech seems to follow a LOS (line of sight) protocol. When marking your Waypoints, make sure you can visibly see your droid going to the Waypoint and that it is also not too far from your last Waypoint marked. You can also customize the astromech's appearance. Can be found in a Buried Treasure with any of the different treasure maps.