Click "Ringtones" and begin to customize your ringtone library now.
Transfer Ringtones from Device
To back up ringtones to iTunes, you only need chick "Transfer Ringtones from Device" >select the ringtones>press "Start" to start copying your custom ringtones to iTunes.
DIY a Ringtone
Click "DIY a Ringtone" > Select a song>customize iPhone ringtones> "Create". That's it. You can preview the ringtone by clicking to make sure that's the part you want.
Note: Ringtones should be less than 40 seconds, and manually setting the start time is available.