The video which should not exceed three minutes, could be realized in first person, as if it were a true story, or in third person or in any other suitable manner.
Do not limit the creative ways to make the most out of the valuable material collected and processed during the years of research.
In case that you haven't been collecting videos during your research work, you could always elaborate the collected photos to gain a higher value of content and scenography.
It is important to remember that the purpose of the video is to tell the general public about your own research: The simplicity of the terms used or their explanation, in case they are needed, will be an important factor during the Jury's judgment.
Try to tell with a three-minutes story your three years of research; but it is a "story"!
Avoid slides as usually presented at congresses; Try to be creative and use outcrops, rocks, lab instrumentations along with non geological examples to attract non-specialists in your research
Explain why and in which way your research is important, fascinating, relevant for society!