1. Take Apple 7 as an example. In the "Personalized Color Ring Back Tone" option, you must first turn on "Cool Dog Music" on your mobile phone.

2. After logging in, click the "Expand" button in the upper left corner of the interface.

3. Click "Personalized Color Ring Back Tone" in the options list.

4. After entering the interface, there is a "ringtone" option at the top.

5. Click to enter the ringtone interface, and you can choose songs as ringtones.