It is a board of engineers (which will become your peers) to ask about specific categories of skills. You don't need to know everything but it helps to be well rounded.
I applied online. The process took 2 months. I interviewed at Northrop Grumman
Interview
It was pretty ok. They called and we talked for over an hour. They offered me a job but couldn't give me hours I needed as a single parent. They didn't care to try to help work around so I could at least get my kids from school and
I interviewed at Northrop Grumman (Clearfield, UT)
Interview
Straight forward phone screen followed by interview with a manager. Thought it would be a straight forward technical interview but mostly got asked very odd and awkward open ended questions. I got a sense for what the interviewer was looking for but for the most part I felt like I was trying to read his mind unfortunately.