You can buy an Exchange Traded Fund (ETF) like the GLD that trades gold (easiest way.)
You can invest in the companies that mine gold (a bit more risk.)
or
You can go to a coin shop and buy gold and gold coins from them.
Keep in mind that if you go buy physical gold from the coin shop that if you buy it and then turn around and try to sell it back you will get less money than what you paid for it - the shop keeper needs to make money too. Also plan on someplace to store your gold like a safe deposit box or a home safe.
Gold is not an investment. Its a hedge against inflation
or in case money becomes worthless. See link
http://www.wikihow.com/buy-gold
I leak to stratd buying gold. In the market.
