Test is same for all subjects. It is on the same pattern as GAT general but difficulty level is a little higher. It is a highly competitive scholarship. NTS will shortlist 30 candidates on the basis of test score and keeping in considerstion the provincial quotas. If you are from Punjab, you should aim for 85. From other provinces, aim for 80. But some might have cutoff at around 75 too (GB or Balochistan). After shortlisting, your names will be forwarded to Commonwealth Commission. There you will have to submit online form alongwith personal statement, reference letters etc. and will have to take IELTS. You will give university preferences and will also have to apply to universities separately. 900 names are sent to Commonwealth commission from around the world including 30 from Pakistan and the commission awards scholarships to 300 students. So even after being shortlisted, there is only one third chance of being selected. The process is long and final selection takes place in next April and classes commence next September. Me and one other person on this forum were shortlisted last time but didn't make the final cut. They do not give you any reason for not selecting.