• Download bp-activity-comment-notifier.zip
• Unzip it , It will be unzipped to bp-activity-comment-notifier directory
• Upload "bp-activity-comment-notifier" to your wp-content/plugins directory
• Login to WordPress dashboard and go to Plugins–>Installed
• Activate the "BuddyPress activity comment notifier"
• That's it. Now, comment on someone's status and ask them if they see the notification or not ?