I applied online, then was advanced to video interview stage. It is a passive interview with nobody on the other end, but instead questions are given to you with limited preparation time before your camera starts recording.
I was advanced to the final stage which included Red Bull flying me out to LA for a business case presentation & a reception dinner. The entire two day trip was an evaluation period, with all of the conversation contributing to the hiring managers analysis of you.
We were told that 2500 applications were submitted to the internship program. 35 applicants were flown to CA for final round competing for 7-8 positions. This is a VERY competitive position.