Slitherine

I would like to accept one of the challenges on the multiplayer but get a message that i need required campaign PIKE_MODV1.2 & required scenario is Skirmish. Im playing the game through Steam. Can I download these campaign/scenarios and if so where and how do I do that?
Thanks

It is not an "official" mod, but something someone is testing.

See: viewtopic.php?f=477&t=98056