@selvestre Short answer, you can't.
Surface Hub is designed for shared spaces, such as meeting rooms and huddle spaces. It's meant to be used by multiple people when collaborating. As such, it has it's own device account and does not require a user to login to the device to use it.
Please read this page on the Admin guide for more information on the differences between Surface Hub's OS (Windows 10 Team) and Windows 10 Enterprise.
