You can create a review from the review dashboard which will also be the landing page after you've logged in.
If you're in a review and need to get to your review dashboard, you can get there by rolling over your name (in the top right hand corner of the screen once you're logged in) and clicking My Reviews.
You only need to know the title of your review to get started. This title must be unique. You can add additional review information from the Settings tool.
You can view a short video on how to create a new review, as well as how to then invite co-reviewers to this review below: