I applied for the Management Trainee program in 2016. The process took 2+ months with 4 rounds in total including: 1, CV screening; 2, Online Assessment; 3, Group Discussion; and 4, Individual Presentation + Final Interview.
The total process in general was not so difficult as other Management Trainee programs but the important thing here is that they recruits the right people, not the smartest or brightest people due to the nature of the job. You have to be really motivated and resilient or else you will not be able to stand the job long.
I recommend you to do research and understand well on what you will do when you are in the staffing industry (or so called headhunting) before you take any next steps.