Reached out to Amplify through their career page, and was contacted by a recruiter. I was given an online coding test to complete in Python. After that, was given a phone screening, which was a combination of general computer science questions, personality questions, and one coding question. That went well, so was invited in for an in-person interview. The in-person interview was comprised of three one-hour meetings with different engineers. The first was focused on system design, the second was focused on algorithm design, and the third was a combination of personality questions, experience questions, and a bit more system design (because that was obviously my not-as-strong side).
It's clear that they care a lot about finding people who are really passionate about education and making the world a better place. If your personality fits, and you have good computer science fundamentals, they will be forgiving if you don't get exact details right on questions (I know I didn't).