You should have a modem in your notebook. The modem can be either an internal one or an external. Most notebooks have an internal modem.
You can simply find the place in your notebook where you can plug the phone jack, plug it, make sure that your modem drivers are fine and the modem is communicating correctly with your mother board, then establish an internet connectiont through the control panel, dial the number, and then you are connected.
That's the very generic case, now if you can be more specific telling us, what is the notebook type and specifications, what is the OS it is running, this would be great as it will help a lot in posting a specific reply to your inquiry.
Thanks.