Your overview is the first part of the introduction of your FYP reports. It explains the immediate context of the problem you want to solve, tells the reader why the project area is important and identifies your motivation for solving the problem.
For your proposal, the overview will probably be less than one A4 page long, but you will probably add to it for your progress report and/or final report.
For further information, you can read Writing a Research Paper by Purdue University's Online Writing Lab (OWL).
When you get to your final report, OWL suggests that you add the following regarding the scope you chose: