Find "Notifications"
Press the menu icon.
Press Messages.
Press Menu.
Press Settings.
Press Notifications.
Turn on notifications
Press Received notification to turn on the function.
When the field next to the menu item is ticked (V), the function is turned on.
Turn on message tone
Press Play notification sound below Received messages to turn on the function.
When the field next to the menu item is ticked (V), the function is turned on.
Select message tone
Press Notification sound below Received messages.
Press the different message tones to listen to them.
Once you've found a message tone you like, press Apply.
Exit
Press the Home key to return to standby mode.