Trying to understand SEO open for comments

Trying to understand SEO open for comments

I am trying to understand SEO, and this discussion is open for comments.For those of you that don’t know, SEO is Search Engine Optimization. Basically, when Al Gore created the internet, search engines developed “bots” that scrubbed the internet indexing the contents of pages they came across. Since then it became indexing keywords. Now that nearly everyone is on the internet, and a lot are providing content (all of which is true), search engines needed a way of optimizing the content, so that old content doesn’t show up first, like my results from a medical examine 10 years ago, but more relative content all the while removing “spam” from the results as well to help curb “phishing”. That is my overall understanding of it.
I know there are a lot of blanks. But for me, my issue is not so much what it is, but more how to make my site work with SEO, and get me higher on the search results list.
My site is running on WordPress with the Google XML Sitemap plugin. This plugin is supposed to be the best for SEO, and I’ve got it configured right (really simple to configure) but I couldn’t fine a spot on WordPress to setup MetaTags. And I thought MetaTags were needed for SEO. Is it the tags on the post? Or is it somewhere else? Am I missing something? So I doubt I will get responses from Google searches, but Facebook responses would be just fine. As long as I get it resolved.

*** UPDATE ***
I have since switched out my SEO plugin to WordPress SEO by Yoast. Not difficult to set up, definitely go through the tutorial. Though I am still trying to understand SEO, and would like to reiterate that this is still open for comments. One of the tools I recommend (and the WordPress SEO by Yoast gives you a direct link to it), is the Google AdWords Keyword Search tool. It neatly breaks down the phrase you may want to use for a keyword and then makes recommendations on like phrases and rates them based on search results.