Download the installation package for the most recent version version of Add Attribution and upload the contents to your WordPress plugins directory.
Activate
Add Attribution for FeedWordPress
through the WordPress administrative interface, underPlugins.
The interface for creating and modifying boilerplate text is added as a new settings box under Syndication –> Posts & Links in the FeedWordPress administrative interface. To set default rules for all syndicated posts, edit the rules under the global defaults page; to override the global defaults with specific rules for any individual feed, select that feed’s setting page from the drop-down list at the top of the page, and create new rules which will apply only to that feed.