hi i have an unlocked iphone version 1.0.2 and i was wondering if anybody can tell me step by step on how to upgrade the firmware and keep it unlocked

Btw how do we browse through the folders for the iPhone like to go to apps and stuff. I go to my computer click on the iPhone icon and put explore and it only showing the pic. I tried the ibrick its not recognizing my phone after I downloaded the installer please help guys thanks