Joining?

I’m making a baby shrug. I’ve done the left side and now I’m suppose to be starting on the right side. It says to join the yarn and purl to end. I got the purl part but do I just start purling or do I some how attach the yarn to something and then purl?

You can just start purling with the yarn, and when you’re done you can tighten up where you joined when you weave in the end.

Thank you!!!