I applied in-person. The process took 2 days. I interviewed at Arconju (Madrid) in Sept 2012
Interview
I called them while I was still a student, letting them know that I would be available for a summer placement. After a brief chat, they offered me to come around and visit the studio in order to show me the type of projects that they were making at the moment and what I would be doing in the case that I worked there.
Interview questions [1]
Question 1
They asked me about what kind of architecture was I interested on adn why. They also asked me why did I want to work in their studio.