Many officiating organizations use ArbiterSports to register officials for their leagues. If your group manages its registration through ArbiterSports, you can access the registration by switching your views to the Central Hub for your group. Your group will have created a tab or a button marked "Registration," which will direct you to the forms for the various sports and competitive levels you wish to register for. Click on the appropriate form, and follow the steps to complete the registration.
For more information on how to register with your organization, check the Announcements page for your group, or contact your assigner.