There are different user levels available in MediaLab. The level provides a basic way to restrict access to the core features of MediaLab. In addition to the user level, control flags can be used to grant access to specific features to users of any level (e.g. share). The control flags only apply to uploaders and users.
An owner has the same access as administrators, but in addition they can access subscription info and SSO-related security settings. Owners are protected accounts and can not be removed.
An administrator has full access to the Lab. An administrator can manage the folder structure, upload and share files, but also create new users and manage the available addons (pull/push).
The media manager has full access to all the media in the Lab. The media manager can also manage the folder structure, upload and share files, but in contrast with the administrator, the media manager is not allowed to manage users, groups nor manage push and pull profiles.
Uploaders require explicit access to folders, by adding an uploader to a usergroup. They can browse the folders they have access to, and add new files to these folders. By default the uploader is not allowed to edit or remove files. For that, they can be given the "manage" flag, allowing them to manage the folders they have access to.
The user also requires explicit access to folders through the usergroup system. They can view all files available in the assigned folders, but are not allowed to add new files. Using the control flags, a user can be granted access to specific features (e.g. share and download).
For more information regarding the control flags, please read this article.