First off, be sure to read the following information:
Key notes to take away, you need to review 3 different designs/content and each review needs to contain 50 words or more and be meaningful and well thought out.
Provided you have done that, once you post a new thread, it is immediately thrown into a Queue for the staff to look at, review, and eventually approve (takes approximately 24-48 hours). Upon approval, your review request will become visible.
Hope that helps.