You will either see a button that allows you to create a new material or a
list with options to edit any existing materials assigned to the selected
3D model at the Material tab.
For objects that already have a material, you see multiple controls
available to manage the material at the top (Figure 5.2).
Figure 5.2 - Material controls
Here is a list with what you can do with each of the controls:
Material Name: In the text field, you can rename the material. It is
important to assign meaningful names for materials, which will help
you later identify what they represent.