I applied online. The process took 1 day. I interviewed at DLR (Bilbao) in Feb 2020
Interview
It was a phone call. They are super technical so the best advice is to be prepared to get tons of technical questions. It was a PHd student and his supervisor. Also they might be searching for a future PhD student.
Interview questions [1]
Question 1
Where mainly about if I new the equipment and the techniques.