Meta tags is the information that you inserted just below your site title ot <title> tag. In my understanding, this is something that give a more accurate information on what is your site about.
Once you enter meta tag to your site, you supply a good information for the search engine robot and this will then give a better understanding on your site. By the way what you really need to remember was, meta tag is not something that will boost your ranking all the way to the top. This might help for SEO but there is a lot of factor that is needed to get to the top.
Some meta tags that might concern you were;
<META name=”resource-type” content=”document”>
Usually you will have this meta tag in your site, the purpose for the existance of this meta tag was for the indexing of your site.
<META name=”description” content=”Short description of your site”>
Keep this in mind, if you go travelling would you just land in a place without knowing what the most interesting thing in that place?? Same with this meta tag too, it describe your site as what you describe it and SE bot will use this info to attract more people to your site. For your information, a good description of your site must at least more than 8words and not exceeding 15words.
<META name=”keywords” content=”a, list, of, keywords”>
If you are running on wordpress, you don’t have to worry much about this. Most of the theme has the auto keyword based on the keyword that you save. So this should be something minor.
<META name=”copyright” content=”copyright statement”>
You will use this meta tag when you want to keep a copyright of all the articles that you write. So if it were your original post, you’d better have this. By the way not much of us nowadays care about this feature, just write in the copyright in the footer or in term of use should be enough.
If you are interested to check what metatag that you know, just right click on your site and view source. This will direct you the script page of your website. If you interested to make a meta tag for yourself, a small tools that might help you were http://vancouver-webpages.com/META/mk-metas.html
Hope this article could help you in fixing your meta tags confusion.