This quadtree algorithm in UE4 uses another git repository called procedural runtime mesh https://github.com/Koderz/RuntimeMeshComponent you will need both of those plugins to able to run the project.
With my other FFT ocean repository, You will able to create a huge ocean rendering.
https://www.youtube.com/watch?v=UjRsnwchF0E&lc=UgyNedXensVkL1YMsJ94AaABAg