You have a lot of freedom when writing your essay. There are things that you should focus on outlined on the website, but those are just guidelines. The important thing is to really represent what your team is all about! The judges are looking for what makes your team special/unique.
You can start with answering the those main points, and then come up with an outline that emphasizes your strengths as a team!
This site is pretty helpful:
http://www.firstnemo.org/PDF/NEMO-ju...e_regional.pdf
Good luck!