Adding a Comment button

I’ve recently setup my first WordPress site using WP 4.2 and Portfolio Press as a theme. I think I’ve checked the appropriate settings to allow users to leave comments, but I see no comment button at the end of my first post for visitors to do this.

My research shows that it apparently isn’t that simple. Many replies to similar questions seem to involve some css or php editing. I can’t believe that something as common as a ‘leave comment’ button on a blog would require that much work. Am I missing something? Thank you.