Supreme Commander
answering the message of
Use your CD key on Steam to download Supreme Commander.
Use your Supreme Commander cd key and download your game on GOG GALAXY
Supreme Commander
For Steam CD Keys, you must download (HERE), install the Steam software and create a new account. If you already have a Steam account, once you log in, click "Add a game" (located in the bottom left corner), and then "Activate a Product on Steam". After a few more clicks, you will be prompted to type in your CD Key. Thus, the game will be activated and automatically added to your account library.
GOG GALAXY is a fully optional client to install, play, and update your games. It also offers online multiplayer, achievements, chat, game-time tracking and more - but it’s up to you which features you want to use.
