First there is a screener call to see what you are interested in and see if you would be a good fit to continue. They want to know that you like to work on various topics. The if you make it to an in person interview, it's a full day of interviews with different people in your subject areas of interest. You can talk about your research and who you are. Be yourself. These are somewhat laid back. You all also give a research presentation for an hour including Q/A. you have to nail this. Be confident in your work. Answer questions directly. After this day is over, they all deliberate. This is the process for any researcher applying here.