would really like to do this need to know how please
You go to the list of GW forums, by hovering cursor over the Forums link found at the bottom of the green banner at the top of any page, and choose Garden Forums. Once you are there, scroll down toward the bottom where all the forums are in alphabetical order and choose Rate and Review Exchanges.
Or...Here is a link and you can save it to your bookmarks or favorites, if you like...Rate and Review Exchanges Forum
There are (overly simplified) instructions at the top of the page, but it fails to tell you which one of the 3 search boxes to use to get the results for 'just' the Rate and Review Forum.
Here is an additional post of hints and tips, for posting to the forum...
Instructions for the Forum