1. Go to materials on the Home tab.
  2. Click on Edit A Material:

  3. Search for a similar type of material to what you are going to add, or search for the material you want to modify.

  4. Apply a new temperature value to the material you are editing.  If you are creating a new material, you can copy all the input values on your screen, and then type in a new "number" designation for the new material.  For user made materials, only use "number" values greater than 400.

  5. Close the material editor to save.