Well there are several ways you can be a part of Pakistan's Defence System. Do you have a preference? Like Army, Navy or Air Force? I can elaborate on the different courses offered by each Service
For example if you're interested in Cyber Security, the Army has Direct Short Service Commission (DSSC) courses almost every year in which there is a post called Information & Computer Technology Officers (ICTOs). Although you will require 16 years of education to apply for this post and I'll attach it's recruitment ad below.
Other courses include PMA Long Course if you want to join Combat Arms and serve that way. Since you've done F.Sc you could apply for Technical Cadet Course (registrations are open right now for 32nd TCC) and do Engineering for free do 1 year training at PMA and then join either the Engineers, Signals or EME Corps.
If you're interested in joining PAF, you could apply as a GD(P), Engineer or Air Defence. By the way, PAF registrations are open right now and are ending on 8th March so if you're interested in serving this way then hurry up and apply. Navy will probably open registrations for PN Cadet Course somewhere in April/May.
If you need any guidance or any more information on any course, I'll be happy to help. Good luck!
