That depends on whether you're wanting to run the Windows version, or the MacOSX version.
When you purchase ArtRage 2.0 Full, you should receive an EMail with your license key, and a link to download the full installer. The EMail contains full instructions for entering the license information.
On Windows, the license key is entered while you're running the installer for the full version. On MacOSX the license key should be entered the first time you run after installing.
If you'd like to purchase ArtRage 2.0 full, go here:
If you've already purchased, but you have a problem with the installer or license key, drop a note to email@example.com giving as many details about the purchase as you have so we can look at the transaction online.
AndyRage's mantra for graphics engine code:
"Sure - how hard can it be?"