To access the customization tools, click Settings, and then Click on the "Customization" link on the left hand side.

By default, all options in Customization are enabled, with comment sorting being newest to oldest.  Workspace moderators can mix and match enabling and disabling any of these options to change the workspace's look and feel.  Whenever you make any change to this setting, you must click "Save" in the lower left corner in order for the setting to take effect.  You should be able to see each change immediately on any of your workspace's pages.

Please note that all of these changes are purely cosmetic, changing these settings have no effect on the function of your workspace or any access your users have to information.  To permanently restrict access to content, you must set custom page security and folder security, or set the Workspace Security setting to disallow access.