1st stage submit online application form with 4 questions about your motivations, why you want to work for Mars and showing examples of competencies. Then completed online logical tests, absolutely fine as long as you practice beforehand. Next stage was a skype interview, I had difficulties with their technology as the program they use doesn't work on a macbook, so ended up having a phone interview instead. Was told by email it would be a competency-based interview, so this is what I prepared. Overall was competency based but also included procurement specific questions which I wasn't expecting so this really caught me out, so make sure you do some more detailed research!