Three of the Windwalker sites activate entities which power the three mystic glaciers. The entities are the Wendigo, the Gnoph-Keh, and Rhan-Tegoth. Simply place the appropriate card on the relevant glacier to indicate this. When Rhan-Tegoth’s Elder Sign is unlocked, in addition that player’s Priest ability is flipped face-up, so it can be used a second time. If the player has not yet used his Priest ability, this site provides no additional benefit. (In our example of play, the player who did manage to flip his Priest card face-up then failed to actually re-activate it before the game ended.)
Once a glacier is activated, it provides its rewards for all players in every preparation phase. This makes the end of the Windwalker board a sort of race to completion. Near the end (usually for only 1-2 turns) all players are getting 2 treasure, 2 blood, and 2 magic each turn!
Please note that the Wendigo and Gnoph-Keh Monster cards have nothing to do with the Wendigo and Gnoph-Key Windwalker cult board cards. They have the same art, but different text, and the cult board cards do not have the monster deck background (they are the same on both sides), so that you won’t accidentally shuffle them in amongst your monster cards.