"In-Context Comment" lets readers leave comments right next to the content being commented, instead of only at the bottom of the blog post
You can either use the "Install new plugin" on WordPress, or do the following:
Download the zip file (in-context-comments.zip) Unpack the zip file. You should have a folder called 'in-context-comments', containing several PHP files Upload the 'in-context-comments' folder to the 'wp-content/plugins' folder on your WordPress server. It is important you retain the 'in-context-comments' directory structure
Note: This plugin will only affect new posts you write after the installation.