How to transfer incoming call to certain extension?

hello everybody,
i want to make call transfer to certain extension which is coming from the pstn line.
so whenever pstn call coming ,it pick up from one phone then after this call is transfer to corresponding person’s extension as our PBX system.
Till now i can get pstn incoming call but i don’t know how to transfer this call to other extensions . In my system i am using sipura device for pstn outgoing and incoming calls.
so how to write dial plan for this configuration ? please help me to solve this problem .

for a sip device I think it would be # or *2 … tures.conf