The format for this proposal is pretty flexible. But you would obviously have to include a clear statement of the problem, the your approach and plan, and the anticipated results. Another component of a successful proposal is a statement of previous and related work. This establishes your credibility and sets your proposed work in the context of the field. One aspect of a typical proposal that you do not have to include is a detailed description of, and justification for, the budget. No budget information is needed for this homework.
A guess at the length of your proposal would be 5-10 pages.