Hello Bob, Sorry to hear you are having challenges. For the solution to work, you would need the Windows Autopilot deployment profile created with the join type of "Hybrid Azure AD Joined (Preview)", assigned to Autopilot device group, AND the device configuration profile type "Domain Join (Preview)" also assigned to the Autopilot device group. All in addition to having the having the "Intune Connector for Active Directory (Preview)" installed and configured. With everything set, on Windows device, go into settings -> update & Security -> Recovery -> Rest this PC -> Get started, then chose Remove everything. The device should go through a full reset of Windows and go through Autopilot setup.
This feature will not work on a device that has already completed the Windows Out of the Box setup experience, so registering in S4B will not trigger the domain join. Hope that helps. If you need assistance, please open a support case via the Intune Admin portal, Help and support.
Jack Poehlman