Interviewz will start in January as per announced by FPSC. Firstly, medical test will be conducted. Then comes the psychological test. Normally psycological tests are about 2-3 weeks before the final interview.
The interview panel takes interivews in these cities: Islamabad, Lahore, Karachi. Peshawar and Quetta. In each city candidates are normally interviewed according to their roll numbers.
Wish u best of Luck!