How do we become reviewers
Ask LaZeez. He admitted me, Likely anyone who can spell in the email requesting permission will be given the ability to inflict their opinions on the authors and readers. Permission is given separately by site for SOL, Fine Stories, and Science Fiction Stories. You should suggest a pseudonym, if you want to use one. Its best if your reviews are at least modestly entertaining and "fair" to the author. There are instructions not to review stories you hate and knew you wouldn't like because of the tags.
You don't have to give tens to every story. I kind of think of 6 as a C, an average grade for an average story, 7 as a B, 8 as an A and 9 (A plus) and 10 are fairly rare. You can give a 5 (D) if you feel it is merited. Look at other reviews, particularly by Celeste, who did it best, IMHO. On the other hand, the service you provide to the site, its readers and possibly to authors by making useful suggestions is to point out stories that readers might not otherwise have found or read. You are not supposed to warn readers to avoid particular stories. If all your reviews are negative, you might lose your credential.
How do we become reviewers
go here, and follow the links:
https://storiesonline.net/h/34/how-can-i-submit-reviews-for-stories