Custom Contexts assistance required

I’m new to freePBX, So far I have my number working, have my 4 digit extension number working, I need to automate a task, ex. when somebody call(dial) my four digit extension number, instead of asking for entering a 12 digit PIN number, automatically enter it by itself. How can I accomplish that? I can’t find any documentation regarding this module. Any help regarding Dial Rules options and the custom Contexts module in detail will be appreciated.

What 12 digit PIN number??? If you want help you need to give detailed information about your system and your setup.