There's an online application which you should fill out thoroughly with your relevant work experience and education. Then there was an online assessment. This varies depending on the role but mine was a timed written assessment where I had to answer technical and knowledge-based questions (including describing what I would do in scenarios) which were relevant to my role. Next there was a panel interview with members of my prospective team prospective line manager and someone outside of my team from the country office. The questions centred around my motivation for the job and competency-based questions based on the competencies/skills outlined in the job advertisement. I used the STARL method to answer questions - situation, task, action(s) that I took, result and learning (so what I learned from the experience).