Time for action—applying materials to CSG surfaces
It's time to get rid of that grey checkerboard pattern covering the walls and floor. You can apply either a material or a material instance to a surface. We'll discuss the differences later. Both types of materials show up in the generic browser with a green border.
Let's find a material that we can apply to our CSG surfaces. Open the generic browser, and in the filter list, check Material and Material Instance Constant. If you have anything else checked, like Static Mesh, uncheck it.
Click on some ...