White light is great, but with a full spectrum from which to choose, why restrict yourself? Now, you will learn to set a lamp to any color you wish. Use the following steps to add color to Lamp:
If the Lamp is not selected, select it with the RMB.
Pull the edge between the 3D View window and the Properties window to the left until you can see all of the buttons in the Properties window header. Move the mouse over the header of the Properties window. Select the button that has the glowing dot with four arrows coming out of it, with the LMB so the button is highlighted in blue, as shown in the next screenshot.
This is the Object data button for the lamp. When you select the Object data button instead of the button with the still camera on it, notice that the entire Properties window changes.
The Properties window is divided into panels and subpanels. When you selected the Object data button, you opened the Object data panel. Move the cursor down to the subpanel...