First, attach your Curve to the PC using a cable. Secondly, click 'Yes' on the Curve when asked if you want to enter any storage mode. Next, click the start menu on the PC and click computer, then double click the icon for your phone device. Lastly, click and drag the ringtone you want to use into the music folder on the phone. Visit http://www.ehow.com/how_7710103_ringback-tones-blackberry-curve.html to learn more.