New to PLEX - can't figure out how to add a library

So I’m new to PLEX. I created an account maybe a year ago and a friend invited me. I accepted and I can see his media. Then I forgot about it and now am back. I can still see his library, but I would like to add a library of my own. The problem is there appears to be no way to do it. Online advice seems to be that there is supposed to be a plus sign next to library but there is no such sign. In the upper left I can see my friend’s username and when I click it it shows him and then a News feed. Am I supposed to see myself as well?

To add a library you must first install a server or set up the cloud server Plex offers. You cannot add a library to someone else’s server.