General Motors interviews with the situation/response type of interview where they ask about an experience with a scenario (see the included examples) and you explain the situation, task, action, and response (check their website, as they provide the details that you need to give for every question). I see that most interviewers at GM has stated that the interview was simple, but I found it a bit difficult for me; as someone who does not interview well. So, I would suggest that you prepare and practice numerous times before the actual interview.

HR / Recruiter Screening -> hiring manager phone screening -> on site interview -> drug test -> VISA / other documents ->negotiate pay and condition, overall is very standard process and they move fast (it also depend on the hiring timing, in my case is in September, they want to get the last batch in before next year)