Got my dual extruder up and running...How do you make 2 coler/material models?

I did a google search for software like sketchup, 123d design etc on how to create models with different colors or materials so I can use the dual extruders. I am haveing trouble finding these tutorials. I think because I don't know what process is called, not much is coming up in my search results.

One example of what I want to do is I'd like to make an id tag for my dog. I was going to use an existing model of a dog bone shaped tag and then extrude the name of the dog in a different color.

I don't know how to do that and what the process is called so I am sure that is one mail reason wh I can't find any tutorials on it.

Can you good folks give me some direction on how to accomplish this? if you have links to tutorials and videos, that would be awesome.

Thank you all
Bill