First things first: While you can run the new Linux Steam gaming client on other versions of Linux besides Ubuntu, for now it's only supported on Ubuntu.

If you want to try Steam on other Linux distributions, start at Valve's Steam under Linux page. Good luck!

Moving on, to run Steam games you should be running Ubuntu 12.04 or newer on a dual-core system with 2GBs or more of RAM running at least 2.8GHz. You'll also need an nVidia GeForce 8500/9600GT or an ATI/AMD Radeon HD 2500/3600 or better graphics and their latest drivers. Finally, you'll need the newest version of Flash, that's 11.2 for Linux, and OpenGL 2.1.

In addition, if you're running a 64-bit Linux distribution, you may need to download some 32-bit libraries during the installation process. At this time, there are no fully native 64-bit version of the Linux Steam client.

That said, if you've met all the preconditions, open the Ubuntu Software Center and select Steam.

If the Steam client is not on the front-page of the Software Center simply search for in the search window and then select it. 

This will bring you to the program window. From here, hit the buy button. Yes, the program is free but you still need to hit the buy button. You won't be asked for a credit-card number, so just click and go.

At the next windows, you're asked to sign into Ubuntu servers using the Ubuntu Single On account. If you don't have one, click on the New account button and get one. It's easy and with it, besides getting access to the Ubuntu Software Center, you'll also be able to use Ubuntu's built-in free, personal cloud storage service, Ubuntu One.

Once logged in, before you can install Steam, or any other program, you must login as the root, or super, user to your local Ubuntu desktop.

That done, you just need to click Start Steam to complete the installation. This will also download the latest updates to the Steam installer and client.

Next, you need to sign the Steam client license. For most of you this is a no-brainer. Hardcore free software users should keep in mind that the Steam client is proprietary software.

You may run into this error message. I did on both my Ubuntu 12.04 and 12.10, 32- and 64-bit respectively, desktops even though both had more than enough disk space. Just hit OK and continue on. This seems to be a harmless glitch. 

At this point, you'll have the Steam client installed. From here you'll need to either create a new Steam account or sign into your existing account. If you an account on another operating system it will work fine here too. Just keep in mind that not all the games you currently have on your other systems work yet on Linux. 

Once you've logged into Valve Software's Steam server you'll see your Steam game library for Linux. This display will be empty until you've downloaded some Linux-compliant Steam games.

So the next thing you should do is to head to the Steam Store and look for games to download and play. 

Once in the Linux area of the store you'll have about 60 games to choose from. More are coming every day.

For starters, let's go with the popular, fun, and free Fortress 2 game. Click the play button and it will start downloading. Once downloaded, it will be ready to play. 

Unless you have a truly awful Internet connection, you can ignore the time estimate for the game installation. On my 100Mbps connection it took less than a minute for the game to download. At this window just click the Next button and...