The AmazonS3 module allows the drupal local file system to be replaced with S3, where the files can be uploaded or downloaded from S3. I used the following modules to achieve this:

•    Amazon S3(module)
•    Libraries API
•    AWSSDK for PHP(module)
•    AWSSDK For PHP(library)
  • Note: Verify that SDK library meets your system requirements. Refer this: http://docs.aws.amazon.com/aws-sdk-php/guide/latest/requirements.html         

 
Download and install these modules and place SDK library at sites/all/libraries/awssdk.
Check  'Status report'  for information about the installation of  AmazonS3 and AWSSDK.

 
 
Here we go:
 

•  In admin/config/media/amazons3, give your default bucket name which you would have created in S3.