Forgive me if I'm using some of these terms incorrectly but I am following a tutorial on this video: https://youtu.be/W-p3MojvdBA?t=2m41s.
I created a rounded triangle but the actual path still looks like a triangle with sharp edges, which complicates the next step in the video. The guy who made the video suggests going to the pathfinder and clicking unite with the dark triangle selected, but when I do this, nothing happens. On his video when he clicks this button, it unites the blue outline (what I think is the path?) to the rounded corners of the dark triangle.