When you need to work with people on a new topic, a committee, a project, a customer, or anything else, you can create a new Subject.
You can create a subject from the "+" icon next to Subjects in the side menu, or from the Subject index, which can be opened by clicking on Subjects in the side menu.
This opens the subject creation window, where you can give your subject a name, color, purpose, invite members, and select the privacy setting. Click on Create when you are finished to create the subject.