I applied online. The process took 7 months. I interviewed at FAO (Rome) in Oct 2016
Interview
The first phase I was called to take an english written exam that was divided in multiple choice and and then a fill in the blank while listening to a cassette audio.
The second phase was a one-on-one with an interviewer where they asked me to talk about myself and the languages i knew. The more languages you know the better.