You have set your blog to show only one post on the front page. Posts on the front page (even if you have only one post showing) will not show the comment box. Some themes show a link to comments, but yours does not.
You can manually add a link at the bottom of each post to link to the comment section. Or readers can click on the post title then scroll down to comment in your theme.
Here is the link to the comment box on your most recent post:
But notice that if you click on the title of the post, you can scroll down the post to the comment box.
If you want a link to the comment box, then you will have to add it manually in the theme you are using.