You need to know whether your learners will be self registering or whether they'll be registered by the system administrator. Alternatively, you may be given permission capabilities on your Teacher account to register them (because that means less work for the administrator). Chapters 4 and 13 cover registration in more detail. Self registration is the easiest — you simply need to give students a URL or point them to a Moodle link on the organization's Web site. If, however, they will be registered by the system admin, let them know they will receive an e-mail with details about how to access your Moodle course.