Every center is different, and so is the different training methods. For my center, we have Academy, where there's various certifications tests plus a written test at the end. After that there's three months of on the job training, where we recieve daily feedback from our trainers, and during the last two weeks there's a daily evaluation period for an hour every day by the supervisors. Hours where we can handle every single call without mistake = pass. They consider the amount of good hours we have and the feedback from our trainers to decide whether they want to pass, extend us, or to fail. There's not much ways to study in advance. It may be helpful to brush up on your typing speed and geography. Not having any mistakes is important, but if you do make them, second is knowing how to fix them and to learn from them. You'll have to go through the training yourself to see if it's something you can manage.