1. Navigate through your phone's menu to select "Settings".
2. In the "Settings", select "Sounds and Notifications".
3. From the "Sounds and Notifications", tap on "Ringtone" to access the ringtone options.
4. There will be a list of default ringtones provided by your phone. Select "Custom" from the list of options.
5. Your phone will display the list of audio tracks stored on your device. Browse through the list and locate the song you wish to set as the ringtone.
6. Tap on the desired song to select it.
7. Once selected, you will see the song title and artist displayed on the screen.
8. Tap on "Set As Ringtone".
9. Your phone will confirm your choice. Tap on "OK" to finalize the ringtone change.
10. Your chosen song will now be set as the ringtone for incoming calls on your Pantech Impact.
Note: If the music file is in a format that your Pantech Impact does not support (like an .ogg), then you may need to convert the file to a compatible format before it will work.