Hi Deena, I received your intro post as a report to the moderator. I realize it is confusing the first time you post, but hang in there, you WILL figure it out!
To post a reply onto a thread of messages like the welcome thread (A forum is a grouping of threads about one topic, a thread is what you click on within the topic to read all the posts under that particular idea or thread), look up at the top of the thread, in the gold area, you will see "Post New Topic" and Reply to Topic" "tabs". Choose the reply tab, then a new window will appear which you can write your reply, then at the bottom of that, you can hit the Sumit reply button.
Check out the frequently asked questions area, the f.a.q. purple/blue little tab above, it may help you figure things out.
Please post often!