When a teacher starts in a new position in any school, they have to learn a new culture because no two schools are the same. While the teacher should be able to figure out their classroom and curriculum, the other aspects of being a teacher in that school can take some time to learn.
The best placed people to do this mentoring would be the staff in the school. The suggestion I would have is that any new teacher to a school would be paired up with a mentor who would be there for the new teacher to talk through routines, etc.
The above would be for brand new teachers and teachers that have moved from other positions.