When you install this package, a Torus, and a Directional Light will be added to the scene, as well as a floor grid. There is nothing particularly special about these instances, except for the fact that they are all using the VertexLit sample material. The interesting thing to notice in this sample is that the light properties are connected to the VertexLit material via the logic diagram "LightToMaterial". All this really does, is connect the position, direction, and color properties from the light to the material properties used to render the grid and torus.

You may also notice that the LightIntensity slider used on the GUI is connected to the material DiffuseIntensity with a multiplier. This means you can control the DiffuseIntensity directly with the slider in the top right corner of the screen.

Try changing the color properties of the light. You can select the light and move it around with the transformation tools.