You first talk with the head of the department where he asks numerous questions based on your resume and questions to get to know a little bit of your personality and then the associate professors. You also get to see the lab if they like you. You meet all the co-workers. If they like you alot they might ask for a second interview with their technicians and other administrative members of the group that can ask you more questions regarding stuff you put on your resume and also to see your personality.