It is not that easy - there some setting which needs to be done in order for this plugin to work fine with your page and Google: So here are the steps:
1. Go to the wp-admin and in your WordPress Dashboard click on Users. Fill in your personal information - e-mail + web site (your own) + Google Profile page which may look like this: https://plus.google.com/XXXXXXX
2. Go to your Google Profile Page and in the About Menu add your site. For example you can write: I am blah, blah, blah and my site is: ..... It is important as you interlink the pages!
3. It is important to have rel="publisher" on all your pages. Usually I am using the top menu to put this link. Simply Add on your top or footer menu "Find us on Google +", or "Google +" and link it to your https://plus.google.com/XXXXXXX
which MUST BE the same as in point 1!
4. On the very top in your dashboard you must find "Screen Options" - open it and make sure to check "Link Relationship (XFN)" for the menus!
5. Open the "Find us on Google +", or "Google +" menu and in Link Relationship (XFN) type "publisher".
6. Go to your Yoast WordPress SEO plugin >> Titles & Metas >> Homepage & Front page and under Author metadata choose your name (filled in point 1) + add https://plus.google.com/XXXXXXX
(the same in point 1 and 3!)
7. To check if everything is working just fine log in to your Web Master tools and go to this link: http://www.google.com/webmasters/tools/richsnippets
- it will show whether everything is working correctly and which fields needs to be done!
If you follow all 7 steps you will see your picture next to your link :-) This will help your site boost authority and trust which will lead to better traffic (more people click on links with pictures!) and better results! :-)
Here is a video on the topic: