After a person is shortlisted based on their resume, they get an interview call which could be in-person or over Skype/Hangout/Phone. It is followed by an offer letter, which when accepted leads to a background check.

I applied online through the ASU student worker portal. Shortly after, I received either an email or a phone call requesting an interview. I attended the interview, and within a couple of days, received a phone call from my interviewer (head of the program) asking my availability. I was flexible, and so she then asked when I could start. I gave a couple of days to confirm my decision, then started the following week or so.