How to set a custom ringtone for jailbreak iphone?

1. Open itunes and select "Add File to Library" in the "Files" directory in the upper left corner. Here is the location to open music, add music to itunes, and select the music you want to set. 2. After opening the Program Introduction, select the Options tab, and then change the stop time of the song playing time to 40 seconds. After making changes, click OK. 3. Right-click the song and select "Create AAC Version". 4. After "Create AAC Version", select it and right-click "Display in windows Manager". 5. Right-click the song and select "Rename", just change m4a after the name to m4r. 6. After the change, select the ringtone from the list on the left side of ituns software and add the ringtone just made. 7. Select the ringtone option and check the box in front of the synchronous ringtone.