Write up, or explanation on your approach. Write a paragraph, or two on this.
Write up, or explanation on any assumption that you have made. Write a paragraph, or two on this.
Write up, or explanation on functions that you were not able to implement. Explain challenges faced, and effort you made to resolve it.
Write a paragraph, or two on this. Consider this your way to defend yourself and explain the effort made.
Write up on lessons learned. Write a paragraph, or two on this.
Write up on ways to improve it. Improvement could be something you could have done different, but was not able to do because of scope, or time did not permit, functions that you were not able to implement and the reason for not doing so, a different way of approaching the problem etc. Write a paragraph, or two on this.
Include the source code that you have written. Copy and paste it in the MS Word document.
Write up test conditions that you have tested. If you have tested for any positive condition (conditions that pass the program), or negative test (conditions that will make the program not perform), explain those scenarios.