My first and only interview for the Project Planner Traineeship was quite interesting. It was solely scenario-based and I felt that no matter what response I gave, it was not good enough. I do have a background that is not directly linked to this position, but I was willing to learn, and since this was a trainee position, I thought that it would be fine.
I would not prepare much about yourself and background, since I was not asked a single question about myself or my experience.