Once you have purchased FilmConvert, you will be emailed a license file in the form of an FKV file.
In order to use the FKV file:
Download and install the Trial version of the After Effects plugin.
Start After Effects or Premiere.
Apply the FilmConvert effect to some media in order to get access to the FilmConvert controls. For instructions on how to do that, see Applying FilmConvert to your media.
Once you have access to the FilmConvert controls, find the Register Plugin control, which has a single button labelled Open License File.
Once pressed, you will be presented with a new Window, FilmConvert Product Registration.
Hit the Load License File button and browse to your FKV file.