Prior to the interview, I had to submit to a drug test, if you don't pass the test you won't even get an interview (they pay for the test of course). Passing this they invite you to the facility for an interview. Note that these are secure facilities with 24/7 onsite security and entry control systems. So be mindful of what you bring, if you forget something, it will be exceptionally difficult to get it back. Once in, they took me to a conference room where I met with two other engineers. Whole interview lasted about an hour.