Principled BSDF node not shading right I'm trying to texture and shade this archway I have but its not rendering correctly. I added a basic cube mesh and set up BSDF nodes exactly how I have them on my archway and it comes out perfect.

Why isnt it working on the object I created? I've used blendergurus video on the subject to set up the nodes so you know the exact steps I have taken.

Here is the Basic cube(how I want it to show up) and then  the archway I want shaded. notice the color is one solid shade of grey with no brown specs? 

Can anyone help me find the problem here?
You need to unwrap your model. In edit mode select all vertexes and press U -> Smart UV project. It will creates very basic UV for you, if you want go farther, study UV unwraping.