If you already have a Pro Tools | First account, the additional 12 plugins in the Focusrite Creative Pack, will become available. To see them, you must register your qualifying Focusrite interface and click through to the Pro Tools | First landing page from the link in the Download and Activation Codes page.
You must use the same Avid Master account to ensure that Pro Tools can link the Pro Tools | First Focusrite Creative Pack to your existing Pro Tools | First.