I approached a professor at CORS conference in person. A few months late, he got back to me with an email. Then we had a chat over phone, and finally I met them in person for an hour, where they asked me to present my PhD work.

1 hour over skype interview only with the supervisor. Friendly environment and room to explain your experience and hear back about the project and prospective tasks. I also had the chance to ask about the work and benefit details.