[A2A] You apply, get shortlisted based on your resume. Department calls you for a talk in front of other faculty in the department and/or a teaching session in front of students and/or faculty, based on which you are shortlisted further. Then, you are called for a final formal interview with the director of that institute, HOD and 2-3 external experts (usually from other IITs or industry). In the interview, they could ask you anything ranging from your research and teaching plan to HR questions like why that particular institute. If you pass the interview, you are made an offer to join that institute. Good luck.