Chapter 3. Materials
Material is an asset that defines the look of a mesh with various graph nodes that include images (textures) and math expressions. Since Unreal Engine 4 utilizes Physically Based Rendering (PBR), creating realistic materials such as metal, concrete, bricks, and so on, can be quite easy. Materials in Unreal Engine define everything about the surface of the mesh, such as its color, shininess, bumpiness, and tessellation, and can even animate objects by manipulating the vertices! At this point you might think Ok, Materials are only used for meshes but, no, they are not actually limited to meshes. You use Materials for decals, post process, and light functions too.
Creating a Material is a pretty straightforward process. All you have to do is right-click in Content Browser, select Material, and give it a name. Done!