8    Now choose one of your tiles that now has an image associated with it and click the check mark at the bottom of the source editor.  This takes you back to the mat lab with the image now applied to the object.

9    Once back in the mat lab hold down the "control" key and click the next bead beside the diffuse category to open another channel.  +bead (I'm not sure of the keyboard designation for a Mac) 

10   Repeat step 8 but choose a completely different image for B channel

11   You can do the same process to add a third channel if you wish.

12   Now activate the beads in the same columns for specularity, metalicity and anisthropy.

13   Activate bump by adding beads to one or more columns. (you can actually add another separate channel for bump only if you like)

14   From this point on it is your experimentation with changing slider values and tweaking specular and specular halo colors to get the effects you like.

The render is the results of a couple different settings.  The render is on a black backdrop sky and a single white radial light.