Open your mobile network provider’s app or website
Log in with your mobile number
Go to the caller tune or ringback tone section
Browse or search for a song
Select the song you want
Tap or click activate/set caller tune
Confirm the activation request
Wait for the confirmation message or notification
Check if the caller tune is active by calling your number from another phone
To change it, repeat the same steps with a new song
To deactivate it, go to the caller tune section and select deactivate or stop service