First the company invited groups of student to visit the offices at chicago and to answer questions and take three tests: analytic, logical and team work. It is not that difficult. Just be yourself and do not hesitate to ask questions because they will look after your personality to know who you truly are.
Then if you pass these tests they will email you questions and a programming problem to submit. If you match the requirements you will get another interview to explain your code and test your technical skills.