The Library section of the
  browsing pane displays the folder structure for the current site. A new site
  contains only the root folder, Documents. Add new folders beneath the root
  to create the site’s folder structure.
    This task assumes you are in the library of the desired
    site.
    - 
        In the Library section of the browsing
        pane navigate the tree and click to select the location of the new
        folder.
        
The new folder will be created as a subfolder of the folder highlighted in the tree.
 - 
        Click New Folder.
        
The New Folder dialog box opens.
 - 
        Type a Name for the folder.
        
This is the name that will appear in the tree. The folder name does not support the following special characters: * " < > \ / . ? : and |. When the name contains a disallowed character the Save button is disabled.
Note: There is an exception regarding the period: the folder name can include a period as long as it is not the last character. - Type a Description for the folder.
 - Click Save.
 
The dialog box closes and the new folder appears in its
    appropriate position in the tree.