A google plus (google+) button is basically the same as a Facebook like button but for Google+.
Adding one to your pages is quite easy - go to http://www.google.com/webmasters/+1/button/ and "design" your button, then copy the code it gives you and this needs to be added to your posts/pages

You can put it in your single.php or in your loop (normally in the index.php) depending on where you want it in your theme.

If you dont know enough about code/or dont want to, there are plugins such as http://wordpress.org/extend/plugins/google-plus-one-google1/ which can insert it for you, just remember too many plugins is not a good thing.

Posts on one page = the easiest thing to do here is to set up a menu and have your categories as a navigation then when you click on a navigation it shows only the posts attached to that category. See my tutorial here for more info http://www.apinapress.com/wordpress-custom-menu/

If you get stuck, find me on chat or pm me or email me at info@apinapress.com

Dean
(Apina)