If you have I think royal edition, than your guide will be in your steam directory.
If you pledged separately for strategy guide, than you go to the backer portal, products and just download it.
I
I got the whole thing, that is, the "most DLC" edition (which I think was the Royal edition, but may have been the Champion edition, or possibly an edition named after some element currently unknown to man), off Steam. When I look in ...\steam\steamapps\common\Pillars of Eternity\Docs\ the only thing I have is the Manual. Steam insists that the guide has been installed, and that is where I would have expected to find it, but the only things in their are:
pe-game-manual.pdf
readme.txt
OFL,txt
SteamworksNET.txt
So I must be looking in the wrong place, right?
Try verifying the integrity of game cache through Steam. None of the extras were appearing for me either. When I verified the integrity, it found a bunch of files it needed to re-download. All of the extras (except the Novella and Documentary) showed up for me.