Yes, you can add new areas to your project that were not requested on the brief, you can remove others that were, or you can change the suggested dimensions of any of them, but don’t do it lightly.
The brief was carefully crafted by arkitekturo and the suggested areas and sizes are a good example of what a complete and proportionate project for this brief could look like. You are free to challenge the suggested areas, as long as you have a solid reason to do so. If you want your project to revolve around a certain area and you need to make that space larger for emphasis, by all means do it. If you read a study, found a piece of news or otherwise have specific information about how that particular city/neighborhood/site might evolve in the future and want to include new areas to your project that will help it adapt to those future developments, go for it. But always make sure your presentation clearly shows (either in drawings or writing) why you chose to do that so that the jury can understand (and possibly reward) your reasons and overall design process.
This is an ideas competition, so ideas, in all their shapes and colors, are welcome. If you believe the final result will be a better project by making changes to the brief you should (the professional world is full of examples of architects modifying a brief and winning the competition), but it is key to remember that any changes you make must be made thinking about the project and the people who will be using it, not your personal preferences, and you must present these changes in a way that the jury can understand.