I applied online. Two days later I got an email with a time and place for a group interview. I wore mostly black. The group interview started with asking what we knew about Zara, watching a short promo video, then asking about what we saw in the video. After all that they asked us to introduce ourselves, availability, why Zara?, past experience, etc. The whole thing was very basic and easy. Just make sure you do your research about Zara, their parent company (Inditex), and their various other brands (Massimo Dutti etc.).