They user guide says "Select the Auto register enabled checkbox to enable auto registration when using external authentication methods. Refer to the External Authentication Methods section, for further details, as described on page 213". So if you open page 213 it says that you need to activate and configure external authentication methods (Admin > Configuration > External Authentication Methods page)
Thank, but on (Admin > Configuration > External Authentication Methods page) , No records to display ? how can i add the detail ? no openid, facebook & twitter just like in user guide.