You can find the guidelines
here. A big tip for all authors! I really really really suggest you write your stories in a utility like "word" or wordpad. By doing this, you will have a copy of the story you can work with.
Then, when you submit a story for review, If it needs changes, I will send you a pm telling you whats wrong with it. This way you will have a chance to correct and resubmit your story without having to do a total rewrite (at least in most cases).
The vast majority of stories are rejected because of a few lines and sometimes even a single phrase in the story. Very few are rejected because the whole story is flawed.
By following this process, I think we will all be happier in the end. You save work, and I get a chance to help you be better authors!