The first interview is 3 hours in length, and is split between 2 interviewers (typically the floor managers). The questions are behavior based, and should be answered in STAR format. For the supervisor position, they are looking for answers that really show your coaching abilities and how you took on leadership roles, and what you did specifically that made you stand out. There are key behavior roles they are looking for with each question asked, and you can ask what the key things are that they are looking for. You need to prepare in advance and come up with a bunch of scenarios that can fit different examples to exemplify your ability to lead.