You will find the ability to REPLY to an existing TOPIC at the top and bottom of each Topic page.  At the top of a Topic page you can click on the REPLY TO THIS TOPIC button which brings you to the enter reply box.  At the bottom of a Topic page, click into the REPLY TO THIS TOPIC box and begin typing your reply.    Click SUBMIT REPLY when you are finished typing   There are additional options you can utilize when posting a reply   Quoting a Post in your