Process began at Job Fair at my University. Was contacted for a 1:1 campus interview, which was easy behavioral style questions (Tell me a time when you...). The interviewer only asked two questions and it lasted for 45 mins, he was very respectable and easy to talk to.
A month later I was contacted for a phone screening, also was pretty easy. Consisted mostly of 'fit' questions and harder behavioral style questions. (Tell me what you want to do and how your experience relates to that...)
Shortly after that I was contacted for an on-site interview which was a full day (6 interviews) with people from the department and higher ups. Slightly intimidating, more exhausting than anything. Some interviews were easy, some were difficult, all of the interviewers were very knowledgeable and respectful. The night before consisted on a top-notch dinner with your host, and a stay in a very nice hotel. Your host is simply a mentor, typically younger with less experience. Easy to relate to, mine had gone through the same process I was and would answer any questions you had.