This is just a sample post that I've added the label "portfolio" to, so you can see how it works. Clicking on the Portfolio title will bring up all the posts to which you give this label. You won't actually see the label applied to the post, from the "front end" of your blog, since under Layout / Blog Posts, I've unchecked the box that would allow it to be seen.

I've also unchecked the boxes that would allow your name, date, or comments to be seen (again, since that's how Persisting Stars is structured).

This is another sample post with the label "portfolio" applied to it. As you can see, even though it's a separate post from the other one, it comes up on the same page.