Here's how to post comments:
1. Click on the link "Comments" under the text you want to comment on:
2. Write your comment:
3. Check the box "Name/URL" (DON'T mind the Google account stuff):
4. Write the name you want to use, URL (blogadress, homepage etc.) is optional and can be left blank. When you're done and happy with your accomplishment, hit "Publish your comment", and voilá!