If the laptop is wireless capable then you will need to enable it by switching it on. Sometimes Fn& f8 simultaneously but check your manual.
If not you will need either a wireless pcmcia card or a usb adapter to enable wireless networking.
Once the laptop is working wirelessly you will need the encryption key (16 digit alphanumeric number on the livebox) that will allow the laptop to use the livebox and press button 2 on the Livebox (I think if it is the old triangular type )whch allows other devices to connect to it.