To reply to a post, you must first be logged into your account. Use the Search function located on top of the main menu at the top of your screen to enter the company name or ticker symbol. This will take you to a Company Snapshot that includes a link to that company's board.
On the Bullboards Page, click on "Rate and Reply" link at the end of bullboard post:-
Click on Reply Button to Reply the Post
Enter Reply in the Text Area and click on POST button:-