Instructions
Launch your favorite web browser and navigate to: "www.lego.com."
At the top of the web page, click on the "Play" button, then the "Downloads" button and finally click on the "Digital Designer." link.
Under the "Get Started" option to the right of the screen, click on the "Download Now!" button. Select your operating system (either Mac or Windows) and then run the installation program after it has finished downloading to install the software on your computer.
Launch the LEGO Digital Designer software. The middle screen will be your workspace, and the button bar down the left side will list the difference LEGO pieces that you can use to build your car.
Click on the LEGO piece you want to use and drag it to the workspace to use it in your design. Connect the appropriate pieces together to build the basic shape of your car. To rotate your workspace to see the LEGO pieces from different angles, use the arrow controls at the top, bottom, right and left of the screen to rotate your view.
Click on the "LEGO Design by ME" and select the "Share Online" option to upload your newly designed LEGO car to the Internet for other users to enjoy.