In order to do so, click to edit a Branch (1) and move to the Files tab (2).
Click to upload a file or drag and drop it in here directly (3). As soon as the file is uploaded you can set its visibility, whether the learners will be able to view it or not (4).
From now on, the file is attached to the profile of all users that are members of this branch (5).
and in case the administrator allowed the users to see the file, it is also available to them through their account information (6).
The same stands for the Groups, so the administrator can edit a Group and through the Files tab attach files to the group's users.