Newbie here, how do I Post/ send a message??

You just did! It's not really a "message" as such, it usually involves a question about a problem with your Mac or the software. Pick the right forum (for instance, you posted in the Lion forum, but your profile shows you're running Mountain Lion) and post a question; then wait for someone to post a reply/suggestion - depending on the complexity of your problem, you may get many answers or none if no one knows of an answer as we are all users just like you volunteering our time to help. By default, it is set up for you to get email notification when someone posts an answer, so all you need to do is click on the link in the email to get back to your thread (may have to sign in again).

Thanks from another newbie. Succeeded in posting a query, but have no idea how to respond to a couple of helpful response messages. No hint from the site or format; thankfully yours had the word "Reply" at the bottom which made it easy. What to do about replying if that word doesn't show up? And/or why doesn't it?

Once you login and then select the question/answer, "reply" will appear at the bottom right corner.

There are tutorials posted at top right side of the "Welcome" page.

Best.