I starts with Resume Screening, then an Interview, then a Coding test. Overall, it was not super difficult because I've had similar experiences previously. In addition, my Professors also gave a good recommendation letter, so it wasn't too bad.

I emailed the professor, who scheduled a call to speak with me. It is helpful if you have a pre-existing tie to MIT. Definitely varies depending on who you reach out to, but very worth reaching out in the first place.