The Board On/Off toggle is as simple as can be. This option allows you to make it so your board can only be viewed by those given permission by the admin(s).

To do this...

Access your ACP (Admin Control Panel), then under "System Settings" it will say "Board On/Off". Click on that option to edit the viewing off your board. It will then come up with the new page giving you two entire options. "Turn the board offline?" option, and the "The offline message to display". First, you will need to click on Yes or No depending on if you want your board off or on. Then, if you choose to, you may type in a message that will be displayed giving an explanation of why the board is offline. *Remember* this message will only appear if the board is turned "Offline".

If you would like certain members or groups to be able to view the offline board, either click on Find/Edit/Suspend User or Manage User Groups and you will have to go through all the editing process to let them view it. I advise you to only allow Admins and Co-Admins to view it because if you allow members and mods to view it, there really is no point in having the board Offline.