First, they emailed me a questionnaire that had a problem solving test and math test. If you pass that, they send you to interview with a recruiter. After that, you will continually move up the department with interviews.

I applied online, they responded really fast and send me a personality/IQ test to complete. After you pass that, someone from HR will contact you via phone and arrange an in person interview and an in person test (to show them that it is actually you who did the test). Once you pass this interview as well, you will get an interview with your department manager - for me it was with two different managers. After you pass everything they will have you do a drug test before receiving the offer.