Only Admins of Premium Projects can change access levels.
To change the access level of a folder, navigate to the Files feature within your Premium Project:
Here you can see all of the files and folders within your Premium Project. By default, as shown above, the access level of any folder is set to "Everyone".
To change the access level of a folder, click on the "settings" button:
Here you can see the option to change the access level:
Click this to change the access level. This will open a small window prompting you to select the access level for this folder. Use the dropdown menu to specify the access level. Click "Save" when finished:
To see all benefits of upgrading your Project to Premium, click here.