I ran across this infographic by DigitalHawkins; it is probably the simplest way to explain SEO (search engine optimization) to a beginner. Keep in mind that this isn’t the whole story, but it is a great start to understanding the overall idea of SEO.
Cheers!

The Beginners Guide to SEO
All online marketing campaigns begin the same way, you must understand your audience and have a thoughtful approach to reach them.
How to Reach Your Customer Online
First, identify your target audience and develop a Persona around them (their values, their interests, pain points, and what social networks they use).
Next, do keyword research to identify what your targeted audience is looking for online. Be specific, generic keywords may attract more traffic, but they will be a less qualified sales target compared to longer, more specific keywords (those are called “long-tail keywords”)
Third, create content with your Persona in mind, using the keywords that you have discovered in titles, meta tags, and throughout the post. Use a variation of the keywords naturally, as you would if you were having a conversation with someone in person. Link to other sources, both on your website and off, to support your content or to give your reader another resource.
Once your content is created, promote it on social media networks. Build a community of folks who share and distribute similar content, they likely have a following complementary to yours.
Finally, analyze how your content performed online. You can measure this through the number of visits, shares, retweets, and comments it generated. Tweak the title or call-to-action to see which combination works best to hit your goals.
That’s it! Your guide to SEO and content marketing in a nutshell!