can't put texture materials on imported mesh.

I import a .obj mesh. I make a material with some pictures. I try to put that material on the mesh and it doesn't work. it doesn't matter how complex or simple the mesh is either. Here are pictures of the 3 step process. what am I doing wrong?

step1: import mesh

Step 2: make material

step 3: apply material to mesh and watch it change color.

PS. I heard UV maps might be what my .obj is missing - what is it and how do I make it?

It appears that your object either is missing UVs or has the wrong UVs. UVs are texture mapping coordinates that correlate each vertex to a coordinate in the texture map. The 3D modeling program you use should create the mapping coordinates with the geometry. How/where did you create the object? If you try one of the built-in objects (plane, sphere, cube) you'll see that your material works fine.