Ok. So depending on where you are, you may already have an unsecured signal. Click on the "wireless internet connection" icon. If there is a signal close by, it will show it in the window you just opened. If one of them says "unsecured", and has more than one bar (signal strength), click on it and then click "connect" at the bottom of the window. You may have to wait up to 30 seconds for it to connect, so be patient. Once it's connected, you should have free WiFi. From there, you can simply open your internet browser and you'll be online.
If you don't have any nearby signals, you will have to take your computer somewhere that has an unsecured network. Repeat the same process there, and you will be able to browse the internet.