I applied online.
Received an email with a calendar of open dates, within the email it said to select an open interview date "sometime early next week" after getting a confirmed time via email
I went to the in-person interview. Once passing the in-person interview I had a phone call scheduled with a project manager in CA who asked me a series of technical questions about how and why I would do certain things, In my case, everything was about helicopters because that was my background experience.
After this phone interview, I received an email from the main recruiter saying "thumbs up all around submitting your packet to VP of HR and Elon for approval after that you will be getting an offer letter."