There are two authorisations for the digital classbook. You can activate these either for individual users or for an entire user group, for example all teachers. 

To activate the authorisation for a single person, first open that person's profile via the user management (menu at the top right -> "User management").
Here you can search for the relevant person using the search bar and open their profile. Click on "Permissions" and select either the Permission "Manage classbook" (for admins) or "View classbook" (for teachers).

If you would like to give permission to a whole user group, e.g. all teachers, click on "More" in the menu bar at the bottom of the app and then on "Administration". In the next step, click on "User roles" in the left column. Select the relevant user role here and define the permission for this group of people. After saving, the authorisation is activated for all accounts with this user role.