Closed User Group (CUG) is not avalbale in aem 6.3.1.0

[JakeCham]

Closed User Group (CUG) is not avalbale in aem 6.3.1.0.I was following an article which link i have put below.https://helpx.adobe.com/experience-manager/6-3/sites/administering/using/cug.html.

problem is in cant find Closed User Group (CUG) option in page properties advanced tab.i have created a user group though was unable to apply it on a page.