Some of your questions are answered in the instructions they send you, but here's some help.
1. No - this is a design project, not a coding project.
2. That's entirely up to you, to show the level of detail you feel is necessary to explain your solution to the grader.
3. You'll be uploading it as a JAR file, per the directions.
4. I'm assuming you meant 'how deep'. The answer is - as deep as you feel is appropriate to address all of the requirements of the project.
Hope that helps you out!