Do I need to use your terrain material?
Terrain materials are a bit tricky, and there are many ways to create them. Our terrain material was built with the intention of having a splat map as the base. You can build off ours, or create your own from scratch. But the terrain textures should be able to be used for any material.
Where can I get the water documentation?
You can find it here
The angled pieces only come in one direction, what do I do?
UE4 allows for invert scale without disrupting collisions or model/texture normals. Quickly scale the object -1 on the axis you need, and snap it like any other piece.
How do I create my own look up table?
Please see the documentation below from Unreal: Click Here