Struggling to get Join to work
Hello.
I'm totally new to AI and all programs used for graphic design. I'm taking Deke McClelland's One-on-One Fundamentals of AI on Lynda.com.
As part of the training, we are using the line tools to create a heart. I'm supposed to grab both paths and do Command + J. When I do that, either nothing happens or I get an error that says, "To join, you must select two open endpoints. If they are not on the same path, they cannot be on text paths nor inside graphs, and if both of them are grouped, they must be in the same group."
The whole point is that when I get things joined correctly, the point of the heart is supposed to be pointy, but it's not. It's still squared off.

Up to this point in the training, there was another time when I was to use join, but it also didn't work the same way as the training, so I have no idea what I'm doing wrong.
Has something about the join feature changed since 9/24/2014? If yes, would someone be able to advise me on my error?
Thank you,
Rachael