Built in wireless says it all really. If a netwok exists close enough to you and if you're entitled to connect to it (in other words, you know the security key) then you're off and running.
Your operating system (version of Windows) differs slightly from XP to W7 but basically, when the wireless adapter is switched on it will "see" local networks and you choose the one you want and click to connect. That icon appears in teh bottom right hand corner of the screen - the systray. You'll be prompted for the key to a secure network - you don't want to go into an unsecured one - and you input that the first time only and Windows saves the informaiton for the future.
Switching on the wireless chip is sometimes by a tiny switch on the laptop or by using the Fn key and one of the Function keys together - the one with the wireless icon similar to ((0))