Official SwitchCraft updated to version 3.18
Updated mods: CC:Tweaked, Plethora, OpenComputers, Chisel, Quark and more
Type in the modpack name (Official SwitchCraft) or paste the following url into the search box.
Finally, click Install at the bottom right of the launcher after you select Official SwitchCraft from the list on the left. The launcher will handle everything else!