HR would arrange the whole process. It really depends on the team. But mostly multiple people interview and there will be a senior person in the end to decide to make the offer or not. For SDET leader, they mostly look for leadership and technical ability. Expect technical questions. Ability to think. Work to work with team. Action oriented and result oriented. Technical coding is most important.

I was very impressed with the efficiency of the hiring process. After submitting my resume on Microsoft.com/jobs, I did not hear from the team I applied to. But within a week, I was contacted by a different team about a job that was a better fit. There was a technical phone screen which included homework to write code and email it in. Then I was invited to fly to Redmond for an interview. I met with six interviewers in one day, which included my manager, a couple peers, and a direct report. It was a grueling day, but there were no big surprises or questions I was not prepared for. During the interviews, it became clear to both me and to the interviewers that I was qualified for more than the position they were hiring for. They had the flexibility to change the scope of the job (and the level) to better fit my qualifications. The whole process - from first visiting the web site to getting an offer took about a month.