The Vegasaur templates are usually well documented and they also have a free utility to make it easier to substitute your media for the dummy media. In the case of a video wall this might save a bit of time.
Hi HF (Happy Friar). It looks like the opening segments of this video. This site has one, but it is not 1920x1080.
Why not set it to 1920x1080 by yourself in the project settings, as long as you don't change aspect ratio, you can change project resolution to the resolution needed.
FYI, PhotoWall template is quite complex. It consists of several nested projects and has many animation keyframes. You can insert your images/videos, but you can't change the animation (you have to change hundreds of Track motion keyframes)