I co-oped with the company last year for 6 months. This fall they came to campus for an information session. They took attendance at the session, talked about different tracks and how things work. They offered interviews from resume's that were uploaded on our university's career services website. Those interviews were for Tuesday, they attended the career fair Wednesday and at that fair filled slots to interview more people on Thursday. Both interview days are treated equally so if you don't get a pre-select go to the booth at the fair and be really friendly!
The first interview on campus is behavior-based style and also the only interview I had with a case study. It usually is something like: describe what you would do if a line went down. (This may vary based on how technical the position is) They hope you ask a lot of questions. You hear within 2 weeks to go to the 2nd round which they call Superdays. There are 2 dates for Superdays and you go a Sunday night for dinner then interview and things on Monday
Superdays arrival is early Sunday. You don't have to dress up a ton, dinner that night is business casual and not with interviewers, just to explain the program more. It is a chance to meet your group as well, which you will be with the next day to solve a problem and present results. Take time to talk to the current SCMPs, this is more of an informative time than a test of you at all. Everyone is friendly so ask lots of questions.
Monday is pretty intense. First, is the group activity. You get 40 minutes to solve a problem (build a bridge, build a watertower, etc). They are looking for people to highlight other's ideas and skills, time management, and not always overpowering, but listening. Try to split the group into more effective, smaller groups. Don't try to be the leader if someone else is trying. There is an observer during this event for each candidate and your observer is also your first interviewer.
After the group activity you have 3 intervews: Accountability, Growth, and a Case Study. Again behavior based questions and then ask a lot of questions. They call you that night and then give you about 2 months to decide. They are the nicest company and people I know. I think it shows that a bit when they tell you fast and give you plenty of time. They tell everyone that they give you so much time so that you can be really happy with your decision to come to Unilever.