Your lack of experience and absence of preconceptions is a golden time. First, interview your customers (internal and external), to see how the team/company are perceived and what is important to them. Explain to them that you are talking to them first to avoid forming any preconceptions. Spend a bit of time organizing and summarizing your findings before moving on to interviewing your team. By interviewing your team last, you will be able to ask better questions and avoid being locked in to your company/Dept's group think and culture.