Here is how to reply to a topic in the forum.
To select a Forum, click its title.
Select one of the topics to reply to.
You will see the topic contents, replies to that topic, and a place to insert a new reply.
To fill out the reply form, type your reply in the blank box. You can check the box if you’d like to receive emails when people reply to your reply. Then click Submit to post your reply to the topic.
You should see the topic page with your reply.