A program through my High School had an application for an internship at NIH. I applied to the program and then got accepted. Then I was able to research the different departments offered and I was able to select the ones I wanted and reach out to them to see if they would like an intern for the summer. I picked a department and the head researcher said they wanted to meet me. It was essentially a two way interview where he asked me about my studies in high school, my interest in his lab, and my future career goals and I got to interview him about his lab so I could see if it was the right fit for me. I told him right then and there that I would love to intern in his lab and he offered me the job.