For an interview they generally bring you into the back office and one or two members of the management team will go over your resume and some additional questions they think are relevant. After that is completed, they usually walk you to the room that you are interviewing for and allow you to sit in and observe the class for 30 minutes to an hour. Generally, if they like you they will either schedule a "working interview" or call you within the next week to schedule one. Working interviews are unpaid and they generally consist of you coming to the school and working in the classroom you are applying for for a few hours. I have heard of as many as zero to five working interviews being requested before they officially hire you.