As the manager in Career Mode, all responsibilities will be placed on your character. If you lead your team to the promise land of commercial success both locally and internationally, you will be the acclaimed hero. However, should you fail to do this, should you not be successful in one way or another, only your character will be held responsible. You live and die by the success of your clubs, and your clubs by the decisions you are constantly forced to make.
You, the manager, will choose how to build your roster; you will choose the scheme for your club on both the offense and defense; you will choose the game plan from game to game, from season to season; and you will Staff your management teams and personnel, organizing how they should do their job to better help the team and your overall success. Every last decision is in your hands. It's a lot to take in, a lot to ask of just one person, but it's a process that separates the good managers from the mediocre ones, and the elite managers from the very best.