there are the steps involve to use the plugin. 1). downloadthe zipped file from here and unzipped the downloaded file to wp-content/plugins folder of your wordpress installation.
2). in left navigate to plugins and activate the plugin.
3). left menu will have string override menu item.click the string override in left menu. add new string with value to be replace in widgets/posts/or pages.
4).after addition listing will show shortcode to be added to post/widgets/pages. just copy that short code (like [stringoverride id="6"]) to your desired location and save the post/pages and widget.to use in template use function call as shown in bracket( '').
5). in front end check for replacement of string with the value attributes.
If Face any Issue please inform to my mail firstname.lastname@example.org or report issue here. thanks Njoy. :-)