First, the S&P 500 consulting project implies that you will be analyzing one company and propose a viable strategy to regain competitiveness in the US Market. You picked Simon Property Group.
The proposal consists of submitting a cover letter where you need to develop the strategy, use the 5 elements of strategy to implement it, and provide convincing arguments about why you shall be hired by the company to lead this implementation. Present the strategy and develop convincing arguments to be hired for developing this implementation. In that manner, you must assume that you are acting as a consultant to Simon Property Group.