If you already have created your organization facebook page that is a good first step, or you can start from your own personal facebook page. The next step is to create a GROUP. People can signup and become a part of your group – or you can choose to make a closed group. Multiple administrators can be assigned that will help in managing and adding content to the group. A group can setup events, upload images and videos, have a discussion forum and interact with members. (www.facebook.com)
Another way to expand your network is to SEARCH on groups to find other groups that may share common interests with you. Signup for their groups and invite them to take a look at your group. Participate in their discussion forums, post questions and introduce yourself to the group.