When a new listing has been created for your Brand Management account, you may find that trying to search for it on the ProductReview website doesn't work as it isn't shown.
The site search on ProductReview is done through Google Site Search. As this is a third party, it takes time for ProductReview's pages to be indexed and included in Google's data. This indexing can take up to 2 weeks but generally happens faster if your listing has a review or two on it.
Even if you find your listing by searching for it, you should have a direct link to the ProductReview page for it which you can share with all of your customers.