In order to download Atlas, an Atlas License Key is required. See Obtaining an Atlas License Key for more details.
Atlas Download Procedure
Navigate to the Atlas Download Site
Enter your Atlas License Key into the product key box and select the Verify Key button.
If the key is valid, then the page will update with the list of available Atlas downloads associated with the Atlas license key that was provided.
Identify the Atlas Version you wish to download and click the Download button.
Accept the end user license agreement by entering your name and email address to download the Atlas installation files.