One shot interview lasted about 90 mins at the language centre in Frankfurt. Actually it was 2 separate interviews on the same day, the first one with a direct supervisor to the language instructors and the second one with a head of the centre. The first interview centred around qualifications as a teacher, my immigration status in Germany, salary expectation, availability for initial trainings if hired etc. The second and last interview was about how I collaborate with the centre as this is a freelance basis position. Both interviewers are great listeners and their composition helped me answer all the questions calmly and confidently. The advice for future candidates is to do your research as they don't just hire someone who speak the language fluently but lack relevant experiences.