Wi-Fi network can be connected using :
- A wireless transmitter, also known as a Wireless Access Point (WAP)
- A Wi-Fi adapter on every computer that will use Wi-Fi
Once these are in place you can simply connect to Wifi using inbuilt Windows 7 Option.
Click on Network icon near time on taskbar.
A list of available networks will be visible. Connect to required network. If its secured network it would as for security key. Provide key and you are connected to network.