Sorry you're finding things confusing!
One great place to start is the Tour de SixLinks
guide, a guide that takes you through how to do many of the main features on the site. We'll have some video tutorials coming on each section, but they're not there yet!
Great pictures you've uploaded. We'll have better looking discussion areas shortly, as a great place for you to talk gardening an ideas with other interested folks!
As far as URLs, the URL is the address of the web page you're on, up in the top of your browser. The Suggestions section is there for you to give us feedback on certain pages of the site, if things look broken, etc. The URL's there so we know what page you're talking about! It's optional, and if it doesn't make sense, you can ignore it.
One final note - make sure you're using either Firefox, Chrome, or Safari as your browser for now. We're working to support Internet Explorer, and it should be there within a week, but we're not there yet!
Thanks for bearing with the construction process!