Mr.impreza

Hi everyone i have recently installed a haltech sprint 500 in my subaru Impreza classic (first time wiring it in) since installation the rev counter has stopped working,I understand I must find the wires to connect up but struggling to find the right wires and where they go / come from, I have the rpm working on the haltech software but not on my dash , i have the DPO 1 wire from the haltech ecu ready to run up to the tachometer ( this is what i was told to use )