There are too many things to consider as “guidelines” but what you want to do in a high-level should reflect the the brand position and brand promise.

1) Figure our your brand story and how to tell it
2) Develop an outline for the content/script
3) Create a storyboard to communicate the brand story
4) Hire necessary help in creating the video (talents, voice over, animator, videographer/photographer, and a creative agency)

Unless you are a brand expert, I would recommend hiring help for step 1.