OK, so here we are with Google+. Well once you have signed up( if you have already signed up with any of Google's other services you can use the same username and password) you can now check out your homepage which will have this kind of layout.I have edited out any parts from my contacts that I don't have permission to include in the screenshots, other then that this should look just like your page, focusing on the 'stream' area. Maybe without a profile photo of me, if you have got that profile pic then you have some explaining too do, don't you?

So, here we have a familiarly set out layout to those who have used the likes of facebook, with the 'box' to update your status and add to your stream pics, movies, ect. When you decide to add something to your stream you then need to decide which of your contacts to send the update too.  Now, this is where Google+ is a different from other social networking websites like the mentioned facebook.. When you want to add something to your stream and then decide who to send to, you need to decide which 'circle' to send to.

In The Circle

Now 'circle' is the name Google + gives to a group of contacts. You create these groups under the 'circles' section. These are where you store your contacts-you add them to a circle that represents the group of contacts they are. For example when you sign up you will already be given some circles, one is Friends, so you can add your friends to that circle. Say you were uploading a photo you wanted to show the contacts in your friends circle, you would select their circle and the photo would then be sent to that group. If you then wanted to send the photo to another group of contacts, then you would also need to select their circle.

So that's the circle system in brief. Now what you can add to your stream is the classic social networking fare; text, videos, photos and they have also gone the way of the likes of forsquare in that you can post the location are at with the messages you send to your stream.
Next, I'll post on the other features of Google+.