Had a formal interview process with the principal investigator. Gave a ppt presentation to the lab, and chatted with each of them about their experiences and likes and dislikes of the lab environment. Had private conversation with the principal investigator about job expectations and scientific project to be worked on.

I applied for this position via email. The PI called me back, and asked some questions about my experiences. At the end of the call, he asked me want kind of visa I want, and I knew I was in.