Hello, wp8 Kuqi.com team has the answer for you:
This is Nokia 930. You can follow the following steps: 1. Use the original data cable to connect the phone to the computer. Drag and drop the music files to the {Ringtong} folder on your phone; 2. Disconnect and enter the phone settings - ringtones + sounds - ringtones - pull up to find the custom ringtone and select it; 3. Make sure the downloaded music file format is MP3 or WMA,
If you are satisfied, please accept it, if you don’t understand, please ask!