You only need to enter your name - the URL box is optional. Then just hit the orange tab labeled "Publish Your Comment". See that wasn't so bad!
Your comment may take a few minutes to actually appear on the blog. It will appear in two places - within the blue "Comments" link on the entry you left the message as well as on the right side of my blog under "Recent Comments".
If you leave a comment, I will be sure to write back to you! Keep your feedback coming.