It’s where authors submit their works in progress for review and critique. In order to submit you have to critique other works. This site is monitored for trolls, those that don’t play by the rules. I have not had any instances where I’ve gotten a critique that wasn’t honest.
Critiques are best when they are detailed. If you leave a critique explain why you liked or didn’t like a part. Be nice and use academic speech. Don’t just leave positive, happy face, remarks all over because no one learns anything that way.
Join. There are thousands of members and they are all aspiring and even published authors, so they take things seriously. You get great feedback on your work. You are not alone in writing!