I applied online : to be considered, applicants must have a 3.3 GPA or above and be enrolled in a university from their list (which includes most of the world best universities I think).
I was contacted a few days after my application and we planned an interview by phone.
When you apply, you can choose your favorites projects within a list, so it's likely that the interview will include technical questions about this project. I was asked what I was currently learning, some questions about the programming languages that appeared on my resume (about libraries and data structures mainly) and I had to explain an algorithm (SVM) as well to talk about complexity