To access a folder that is shared with you:  

1) Click on the plus sign to the left of Shared Files in the Files pane. A list of users who have shared files with you will appear under Shared Files.  

2) To view the contents of the Shared Files folders, click on the folder and its contents will appear in the Shared Folders view.  

3) Click on the folder that you want to view.  

4) To download files in a shared folder, simply click on the filename.  

5) To upload files to the shared folder currently being viewed, click the button labeled "Upload File" and follow your browser's instructions.