Once you’ve found a supervisor and agreed informally on a research project topic, you must write a one-page problem statement. Your supervisor must formally agree to this problem statement.
Your problem statement should explain what problem you are solving, why anyone would be interested in that, and roughly how you imagine to go about it.
Usually, a problem statement looks like this:
1-3 paragraphs of context.
What is the general setting you are working in?
1 paragraph outlining the specific problem you are interested in.
1-2 paragraphs of state-of-the-art:
what is the closest anybody has gotten to solving this problem?
1-3 paragraphs outlining your specific idea for solving this problem.
1 paragraph on method and deliverables:
What are you specifically going to do and what will you submit? (Interviews, case study, literature study, informal survey, prototype implementation, explorative programming, proving theorems, constructing algorithms, etc.)