Find "Voice call"
Press Phone.
Press the Keypad tab.
Press the Menu key.
Press Call settings.
Press Call forwarding.
Press Voice call.
Select divert type
The current settings are displayed.
Press one of the following options:
Always forward
Always forward
Forward when busy
Forward when unanswered
Forward when unreachable
Divert calls to voicemail
Key in (prefix) 5 (your phone number) and press Enable.
Return to the home screen
Press the Home key to return to the home screen.