How do you send a private message to someone on fanfiction?

There are several ways to view any comments left for your stories by readers...

As the author, you will receive e-mail notification when one of your stories has been reviewed. In the body of the e-mail will be the comment left by your reader and you will find a link for you to respond.

Second, if you are logged in, you can see all of your stats and read all reviews for a particular story together.

Finally, if you browse the category your story appears in, there will be a review link after the title, where you can see all reviews.

Don't forget, it is proper etiquette to respond to each review as this shows the reader your gratitude for their patronage.