Build a Website

I have a small project which is about solving a problem in an organization that needs members(Volunteers) to help them to do the organization work. I have to find ways to make it easier for the volunteers to get connected with the organization in a better way. I decided to build a website that will make the communication between the organization and volunteers easier, but the main thing is (HOW TO MAKE THE WEBSITE FUNCTIONALITY HELP THE ORGANIZATION TO GET MORE VOLUNTEERS) after you find solution to this problem, I need to have Use Case diagram, and Use case templet DFD(data flow), I need four of each for the system. I will chat with you for more details.