I applied online to multiple positions available and was first notified about if I would require disability accommodations about a week after applying. Some time between 2-3 weeks after I applied I was invited to interview in person about 5 days after the invitation was sent. I was nervous at first but prepared by educating myself on the program the position was for and thinking about my experiences on my resume. In the end, what my interviewers really cared about was knowing that I was excited about the position and would look forward to coming into work every day. This made the interview go smoothly as I was incredibly excited by the opportunity. I was told informally about three hours after the interview that they liked me and wanted to move forward and the next business day was given a formal offer.
Just remember, chances are your interviewer(s) are nice people and won't be as intimidating as you may expect. In most engineering cases, they are looking for someone that fits well in a team environment and is intrinsically motivated by the work they do.