I am assuming that you have the basic knowledge and I just want to add up a little bit more on how the stock market works. Now picture it that you are buying a piece of the company by means of buying shares. You get your shares by opening an account with a brokerage who then posts your order in market made so that buyers and sellers meet and all is put to an auction.
To start in the process, open a trading account with the broker of your own choice. Now, in the form of commission, expect to pay about $10 dollars per trade along with the seed money that launches your account.