Well, you actually did when you started this thread. I think I understand your question... on some pages like "recent posts" there isn't a tab to click on to start a new thread. If you're using a computer, try this: from the gray area at the top of the website, select "Forums". From that page, select the forum that pertains to your subject - general discussion, maintenance, detailing, mechanical... etc. When you click on that forum listing it will load all the posts for that subject. At the top of the post on the right you should see a tab "Start a new post". click on it. To reply to a thread you are reading, just window done to the last (most current) posting. Under that is a blank area to reply to the thread. See if any of this works for you.
no, but it still deserves an answer. That's my story and I'm sticking to it! (Next time I'll look closer)