iPhone 7 Plus GSM - IPSW Download

Windows

first of all, you need a Computer and an iPhone USB Data Cable

Download the iPhone 7 Plus GSM File Download And install the Latest iTunes on your Computer
it should noted that there are two bits used in the computer 32/64, you have to download iTunes according to the bit of your computer
put your phone in iTunes or Recovery mode and connect it to the Computer
now open iTunes, Press the Shift Key, And select Update and Restore here you have to choose the file
which you have downloaded for our iPhone