Is there any way for me to get it on steam, or do I have to download it somehow?



If not possible, which Civ iteration should I purchase? I'm between IV, V, and VI, although each are crazily priced at the moment (when will there be a Steam sale?!?)



Note: I have never played before, and in fact just downloaded steam (hence the username).



This little addendum kind of makes it three questions, and so I'm sorry, but any FtP games on Steam I should pick up while I'm at it (nothing too intensive, I'm playing on a very run of the middle laptop not in any way optimized for gaming)

You are aware this site is a competitor of Steam right?

You can purchase it here and manually add it to the Steam client launcher. Might not get you all of the Steam ecosystem features you might be used to, however.

https://www.gog.com/game/sid_meiers_alpha_centauri

Edit: and what tinyE says. This isn't a Steam site. It's a whole other store entirely with no customer-side affiliations with Steam. They don't sell Steam keys, don't give you trading cards, etc. But they DO sell Alpha Centauri.

EDIT: Okay, I wasn´t sure, if this was serious. Self-censoring :)

Easy, guys. captainoob said it already: He knows nothing about gaming.

@captainoob
Steam and GOG are two different stores who sell PC games. You can't play games from GOG on Steam or vice versa. But you can play both, Steam and GOG games on your PC. Your computer is the platform, Steam and GOG are just stores.

To your question: Buy the game on GOG, go to www.gog.com/account, click the game and chose one of the two ways to download it. The blue "DOWNLOAD AND INSTALL NOW" button will install "Galaxy". Galaxy is a client, similar to the Steam client you already have. It shows you all your games and let you install and update them.

The "DOWNLOAD OFFLINE BACKUP GAME INSTALLERS" link will give you a "normal" .exe which only installs the game without the client. You'll have to update your game manually, but... Alpha Centauri probably won't recieve many updates anymore.

It's your choice if you want to run a client to run your game or just the game. Clients like Steam or Galaxy do have advantages when it comes to new games, because they automatically keep your game up to date when there's a new patch. Otherwise they're pretty useless (to me).