Hey!
Great question!
As there are still feature developments to grant the ability to render exports from UEFN, the best way to submit a video will be for the UEFN Entrant to screen-record using software such as OBS. This can then be trimmed (not changed) and submitted per the submission criteria.
Through screen recording, you are able to set these types of parameters. We will have a tutorial releasing very soon that will cover this and how to showcase your islands/experiences.
If you have any more questions, please don’t hesitate to ask!