OK, you guys have solved the problem for me. Clicking the + turned out to be the real key and now I understand be issue about each object having it own set of materials. Since I kind of kney ahead of time the colors I wanted to use. I went off and created a set of materials and then using the + and then going to the list of materials in the model, I was able to successfully assign the wanted material to the portion of the object I wanted to color.