You can use the following documents to learn flying on VATSIM in Pakistan Airspace:

RadioTelephony Basic Guide

ATC – Pilot RT Introductory Guide

Airport Briefings

Following are pilot briefings for flying to/from major airports in Pakistan, which you can use as a reference before flying:

Pilot Briefing – Karachi (OPKC)

Pilot Briefing – Lahore (OPLA)

Pilot Briefing – Islamabad (OPRN)