The process begins with general predictable questions. Q - Tell us about your background. Q - Why do you want to do a PhD? Q - Why do you want to do this specific PhD? After this they asked me to describe the PhD project I was proposing (It was while I was doing this that the institute director interrupted with a question about an aspect of the methodology). The meat of the interview consisted of more specific questions about the specific research project I was applying for, it is important to prepare very well for this part as it is the most important aspect, and the part that they spent most time on. Toward the end the questions became more general again. Q - Can you briefly satisfy me that you will be able to undertake the PhD and bring it to completion within your allotted timeline? Q - Can you describe a recent presentation that you have given? Q - Can you demonstrating to me that you will be capable of writing a PhD level thesis? Q - I'm going to give you one last 30 seconds now to sell yourself (I'd recommend being prepared to do this both quickly and in a steadier manner in case you are not asked the question in this manner). Lastly, at some point near the end usually, you'll a general science question perhaps vaguely related to your project. It is impossible to predict what this will be but it shouldn't be a particularly difficult question. I believe it is just to let them see that everything you are saying isn't just completely rehearsed and that you are competent in your general field.