Manually update to Official Jelly Bean

[ashar07]

I have been searching the internet for a way to upgrade this great phone to the official jelly bean manually with no success . I can not upgrade it OTA as I live outside the US. I have downloaded the file VS93021B_05.S21B_05.P58017.R5.cab (1.1 GB approx.) and want to know the step by step procedure to flash it to the phone. I will be very grateful.

Regards