Read a good book or three, like Investing For Dummies, available at your local library for free.

http://www.investopedia.com/university/b...

http://yourportfolio101.com/index.html/l...

http://www.howthemarketworks.com./

http://beginnersinvest.about.com/od/inve...

http://www.fool.com/School.htm

http://beginnersinvest.about.com/

http://www.ehow.com/topic_558_investing-...

You can also type “how to invest” in the Search Answers box at the top of this screen and get lots of answers.

How Do I Actually Make Money From Buying Stock?

http://beginnersinvest.about.com/od/begi...

Getting Started In Stocks

http://www.investopedia.com/articles/bas...

The Cardinal Sin Of Beginning Investing -- And How To Avoid It

http://www.investopedia.com/stock-analys...

The stock market works mainly on the laws of supply and demand.

Here I attach you a video which briefly explains the basis.