First round HR interview over phone just to introduce yourself and for them to introduce the company and the role to you. Was quite pleasant but nothing out of the ordinary. Second round was a 30-40min Zoom call with someone who will likely be your line manager/team leader. Again quite pleasant, some slightly challenging questions about the industry (at least if you didn't prepare!). Third round involved about 1.5-2hrs worth of interviews with a mix of mid-level staff, 3 in total. The first of these involved both some behavioural questions and a case study with 2 interviewers at the same time. The case study involved looking at a single slide with background info, what main problems/objectives there were to solve for the case, and about 3-4 additional questions to address to help you solve the main problem. They then give everyone 10mins to shut off their video and mic and brainstorm solutions. After that, they ask you to go through your ideas for each question one by one, with additional follow-up questions they'll ask spontaneously to get you to expand on your answers in more detail or to ask for alternative solutions etc, so make sure to write down as many ideas as possible, think of explanations behind your ideas, and think outside the box. The second part involved more behavioural/CV/situational questions, again with 2 other mid-level staff interviewers at the same time (taking turns). My interviewers were pleasant but pushed for answers when necessary. Be prepared to answer in STAR fashion, or at least with good structure, i.e. introduction and conclusion to your answers rather than rambling. The third part involved a one-to-one chat with a more senior member of staff e.g. a Head of XXX. This was somewhat unusual, more listening to them detail how they envision the company and the people on their team to be, than actually answering any difficult questions. I think being genuinely agreeable and listening well, presenting yourself well, is sufficient, and it's also a good chance to ask questions (as are all the interview steps).