Find the sound file you want to use as your ringtone. You can use a music file that's already on your phone, or you can download a new one from the internet.
Move the sound file to the "Ringtones" folder on your phone.
You can do this by connecting your phone to your computer and transferring the file, or you can use a file manager app on your phone to move the file.
Open the "Settings" app on your phone.
Scroll down and tap "Sound and vibration."
Tap "Phone ringtone."
Select the sound file you want to use as your ringtone from the list.
Tap "OK" to set the ringtone.
That's it! Your custom ringtone should now be set. Keep in mind that you may need to restart your phone for the changes to take effect.