I just got my PCC done, here are the details of the process for Islamabad and Rawalpindi people.
In ISLAMABAD:
The process starts from DC office, located in G-11/4 sector. After that you head to the relevant Thana (police station) and get your verification done on the form supplied by DC office. After this step u head back to DC office and they will issue the PCC.
In RAWALPINDI:
Here the process starts from Kachehri (adjacent to Jinnah Park). There you have to find CPO (Chief Police Officer) office and get the form. You need to show CNIC copy to acquire it. Then they will direct you to your relevant thana (Police Station), where you will check for your personal records and get your verification done, after this you are asked to visit Divisional Officer, in Saddar Police Station, to get the final verification. Once that is done, head back to CPO office and get the certificate.
In your case the process may be a little different or can exactly be the same, but it starts from CPO, therefore, when going to CPO office, ask them in detail about each individual step and requirement, because if you miss out even a little thing, you might have to start the whole process over again, which is a big hustle.
I hope this will be helpful. If you have any queries let me know.