Here is a guide to install Steam on Ubuntu 13.04. You can install Steam using the Ubuntu Software Center.
Welcome to Steam, the ultimate entertainment platform. Play games, connect with friends, even create and share content of your own. Join 50 million of your closest friends on Steam. Enjoy exclusive deals, automatic game updates, and cross-platform multiplayer. Plus, now you take advantage of Big Picture mode, designed for use with your TV and game controller.
To install Steam click on the link below:
To install Steam follow the steps below
Click on the Buy button
Login to your Ubuntu One account
Enter your password to authenticate the installation
When installed close the Ubuntu Software Center
To start Steam press the SuperKey and type: steam