If the software is already on your machine,

• On Windows, go to Start -> All Programs -> GenArts Monsters GT -> Install Serial Number.
  • Follow the instructions and choose the option to authorize over the web. Click here if your machine is not connected to the Internet. 
• On Mac, go to /Applications/GenArtsMonstersGT folder and double click on "Install Serial Number".
  • Follow the instructions and choose the option to authorize over the web. Click here if your machine is not connected to the Internet. 

To install the software (if it is not on your machine), go to: http://www.genarts.com/support/downloads/monsters-gt/other-ofx. Click on the link to download the installer.  Follow the instructions to install the software. When prompted, choose the option to enter your serial number. Then choose the option to authorize over the Internet.