Use a tool like Rufus to burn the ISO onto a USB drive (at least 8GB).
It turns a 15-year-old operating system into a supersonic sleigh. If you have a dedicated "retro gaming rig" that never touches the internet, download it. If it is your daily driver, stick with Windows 10 IoT LTSC (or Windows 11 Ghost Spectre) instead. win7 ghost spectre