How to format Directors Portfolio?

I’m currently solidifying my audition material for my directing/theatre auditions at MMC, NYU, BU and Emerson but I’m struggling to find information on the correct way to format a director’s portfolio. What should I include? Should it be in a report cover or binder or portfolio? Do I put the original sketches or scan them into a document with other notes on the show? How long should it be? I’ve been gathering stuff from shows I’ve done but I’m still kind of lost. Help!