1) At the bottom of each post (write up) you will see the word comments.
2) Click on it
3) It should now say post a comment. So go ahead and do that !
4) Below the comment it says comment as and there is a drop down bar- click that drop down bar
5)Click on Name/URL- it will give you a space to type your name (don't worry about URL) and then press continue
6) From there, click post comment, and ta-da-- your comment should appear on the blog.
Easy Peasy !!!