Find "Text"
Slide your finger down the display starting from the top edge of your phone.
Press Settings.
Press Settings.
Press Notifications.
Press Text.
Turn on message tone
Press the indicator next to Sound to turn on the function.
Select message tone
Press Tone.
Press the different message tones to listen to them.
Once you've found a message tone you like, press Back.
Exit
Slide your finger up the display starting from the bottom edge of your phone to return to standby mode.