To answer your question, maybe 3-6 months...

From FPSC's website:

"FPSC usually takes 8-10 months in processing general recruitment case provided number of applications are within reasonable limits and no litigation or complexity is involved. In the recent past, number of applicants, who apply for the advertised posts has grown enormously. Due to administrative and financial constraints, the process of finalization of recruitment cases has been taking longer than expected."

Even if there were any concrete timeline, FPSC NEVER follows it. There have been cases where the timeline from advertisement to appointment has been resolved in a year. While there are many more cases where the process prolongs for 3 three years (AD IB 2017 post for example).

__________________
Humein kya. Tumhein kya. Ap ko kya.