Hello! I had the same problem shortly after signing up for the free CC course, but I eventually found the right tab. I don't remember exactly where it is, but there's a page here that has I think four or five steps, and they're numbered. When you get to that page, there's a black colored tab, with white lettering, and I think it says "Get Started". Press that tab, and I believe you'll be taken to the page that starts your training. It's very difficult to find that page with that particular tab on it, but once you do, it's a go!! Good luck to you!!!
