Additional security is defined through the SQL Server Reporting Services Site Settings.

1. From the top right corner of the SQL Server Reporting Services Home page, click Site Settings.
2. In the Site Settings window's left pane, click Security.
3. To add folder security for specified users, in the menu bar, click New Role Assignment.
4. In the New System Role Assignment window, add the group or user name.
5. Select a role(s) for the group or user and click OK. The Site Settings window displays the new group or user and the role assigned.
6. Exit the SQL Server Reporting Services window.