Circles are the heart of Google+ - they control who you share with and whose posts you see. Find people you know, then drag and drop them into circles that match your real-world relationships.
See what people are sharing
Now that you've added people to your circles, visit your stream to see what they're saying. When you find something you like, add a comment or click +1 to just say "cool!"
To post for the first time, click "Share what's new" - you can include photos, videos, and links. Select the circles or people you want to share with, or choose "Public" so that anyone can see what you have to say.
Getting back to Google+
Click on your name to return to Google+
A red icon means you have new stuff to see in Google+
Congrats, you've made it to the end of this epic email. If you're still seeking answers, check out the Google+ Help Center.