
HTC Desire C
Find "Call forwarding"
Press the menu icon.
Press Settings.
Press Call.
Press Call forwarding.
Select divert type
The current settings will be 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 447836121121 and press Enable.
Exit
Press the Home key to return to standby mode.