I would suggest you to go through step by step guide available on SAMMOBILE or XDA developer first before performing flash as any wrong step will result in bricking your device.
First thing first you need to understand you have brought this handset from Malaysia so the software version it has on it can only be updated via OTA in Malaysia. but as this handset is currently used in Pakistan so the CSS is mismatch with Pakistan ...
I too have Malaysian XME SN960F, and samsung pakistan manipulated me for good 2 months and at the end they said we cannot update as updating it will damage your hardware...SERIOUSLY that's the lamest thing I have heard. Anyhow I did my research and f...