If you already have a Pro Tools | First account, then the additional 12 plugins in the Focusrite Creative Pack, will become available when you have registered your qualifying Focusrite interface on Focusrite.com and clicked 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.