Now that you have a Google Account, you need an invite to Google Plus. Ask someone already using Google Plus to invite you, or go to https://plus.google.com and request to be contacted when Google Plus allows access for everyone.
Creating circles allows you to group your contacts and have more control over who sees what you share on Google Plus. It also allows you to filter information that others are sharing according to circle. For example, I can choose my “Family” circle and only the photos, links, and other updates shared by people in my “Family” circle will be visible.
The following video demonstrates how to verify your Google Account, join Google Plus, and create circles.