G2A's acquisition of Windows 8
G2A's acquisition of Windows 8
you're thinking about buying Windows 8 at the cheapest price, which was G2A. you've bought games there before without problems, so you're on the right track. yes, during the OS setup you'll likely receive a Windows key that needs to be entered. when using a bootable drive, you can use this key to install and activate the version you purchased from G2A. following the instructions in the Linux video should guide you through the process.
I would visit /r/microsoftsoftwareswap. It offers better reliability compared to G2A.