I think you're looking at the wrong version of the docs. By default, docs.ckan.org shows you the docs for the latest development version of CKAN. You need the docs for CKAN 2.1. Try this: http://docs.ckan.org/en/ckan-2.1.1/filestore.html
If you've followed the 2.1 docs and it still isn't working, see this answer: Error when trying to upload a file to CKAN: "Failed to get credentials for storage upload. Upload cannot proceed"