You are asking about posting reviews am I right ? You just look at the tabs on top containing automobile, living, books, electronics, home etc. Just click the tab of your choice for which you would like to write reviews and you will find no of products under the tab you selected, now select a product and start writing reviews. All the best.
I guess you want to post some product reviews, right. If so on the top please click on the tabs like automobile, living, books...........etc. so that there you will find various products, from them now you select your choice and write the review, okey. Happy posting.