Find "Additional settings"
Press the menu icon.
Press Settings.
Press Call settings.
Press Call feature settings.
Press Additional settings.
Turn call waiting on or off
The current settings are displayed.
Press Call waiting to turn the function on or off.
Press Call waiting to turn the function on or off.
When the box next to the menu item is ticked (V), the function is turned on.
Exit
Press the Home key to return to standby mode.