How to lock a page

<accesscontrol>Administrators,Usergroup:Members</accesscontrol>

To lock a page to just Administrators insert the following in the top of a page

<accesscontrol>Administrators,Usergroup:Members</accesscontrol>

Or to Allow editors as well as Administrators put this instead

<accesscontrol>Editors,Usergroup:Members</accesscontrol>

Or to Allow Devs as well as Administrators put this instead

<accesscontrol>Devs,Usergroup:Members</accesscontrol>