"Find the Dun Banner's standard and Vandergrift's sword. Then see Philippa about the remaining artifacts."
This is exactly how you get to the Place to find the Dun Banner Standard, it's also the same path to get to "place of power" I've made a note of it on the video.
From the "Inn" aka bar, go through the underpass where you see two banners, walk through the market area and then make a right and go up the stairs and around to where the little dwarf guard is standing. Continue along this path to get to a wooden door. When you go through that door you get outside by a lake, cross the lake at the correct spot as noted in the video, to get to the place of power go up the path on the hill, to find the dun banner go over the SMALL lake/pond and continue on that path. You'll be fighting a bunch of wraiths here so make sure to save your game and use Quen sign magic.