Help about setting my laptop to wi fi

Hello,

and good afternoon, First i dont own the laptop. my girlfriend used to,she brought it to her dorm and shes aware that the hostel shes staying to is wi fi accessed but we dont know how could she possibly connect to the internet.i read some post/forums that it need SSID and WEP key and others but i dont have any idea to get those. Can you help us? it is ASAP.
The laptop is Windows XP.

-Thank you in advance. :D