Unity Terrain Holes Not Showing

So for my current project I'm trying to make a hole in the ground so I can make a dungeon out of some meshes I've made. The hole applies for the terrain collider, however it does not erase the texture as well. I read on Unity3D manual that "Internally, Unity uses a Texture to define the opacity mask for a Terrain surface. When you use the Paint Holes tool to paint on a Terrain, it modifies this Texture. Thus, any holes you paint are visible only if the Terrain Material you use clips or discards texels based on this mask", however I'm not sure how to enable this or even alter the small amount of settings for the terrain material using the render pipeline.

Any help would be greatly appreciated!