I’m building a house… and when I follow this for assigning multiple textures to different faces in 2.76a, all it does it turn grey. It doesn’t apply the texture. When I do the same thing to a cube… it does the same thing. I’m sure it’s probably something I’m doing wrong… but can’t figure out what since I’m following exactly?
You’re in “Solid” viewport mode, which by its very definition does not display any textures:
You might want to switch to either “Texture” or “Material” mode - you might also have to add a light to your scene.