Hi.  I have an IC-GK 03 keyboard.  I am trying to upgrade my mac OS to the latest version, and the process needed the use of an "option" key.  I am about at the end of the upgrade process, and the reboot needed to use an "option" key.  Would you please go over the exact steps on using the "alt" key on this keyboard (that being said as the equivalent of the Apple/Mac keyboard "option" key). There are 3 keys on this keyboard that have "alt".  Please specify which one I will be using.  As you know, one key has "win" on top/"alt" below.  Another key has "alt" on top/"cmd" below.  The other key   has "ctrl" on top/"alt" below.  Please enlighten me.  This is crucial to upgrading my macOS. Some of my computer apps, and therefore computer work could not be applied if the macOS   is not up-to-date.  Thank you.