Because trailers are so short, the information you convey has to be concise. iMovie’s templates do not leave much room for text. And, the more you write, the smaller the text becomes and harder it is to read.

iMovie provides an outline and storyboard for each template. They are useful and necessary to make your trailer, however they can be limiting. iMovie’s outlines have some suggested text and also show what kinds of shots to include (landscape, close-ups, wide, action, etc).

To help plan trailers with more original text and shots, below you will find a fillable PDF for each template.

Each PDF is fillable, so you can open in an app like Adobe Reader or Preview and easily add your own text. It’s up to you if you’d rather draw in the shots or simply type in what you plan for each shot. Of course, you can always print the PDF before or after it is filled out.

source: http://learninginhand.com/blog/2014/8/6/plan-a-better-imovie-trailer-with-these-pdfs