[Plugin: WordPress SEO by Yoast] Add A Parameter To Head For Description?

I just started using the WordPress SEO Plugin by Yoast and in order to make the created titles work I had to add a parameter to my head as follows…

<title><?php wp_title(''); ?></title>

So, my created titles are working as they should, but my descriptions are all the same when I view my pages source codes. Is there a meta-description parameter I need to insert into my head like I did for my meta-titles? My keywords are all the same as well, so same question for those.

Thanks ahead of time for any help!