You need to have proper visualization and intention of a SOURCE of light. You can indeed help yourself with external lighting, be it artificial, yet the act of inhaling energy when the Sun is at the peak and in an approximation of this kind of light is most powerful and supreme.
Artificial helper of light<Proper Visualisation<Inhaling Sun Energy - all under the will and intent coupled with the focus of the individual produces results and works anytime anywhere.
As a beginner, you can download some pictures of the sun on the internet, inspect and meditate on the picture to proper remembering. Use some relaxing breathing exercises and then try to re-visualize what you just saw. The idea of the Sun, the idea of light must be in mind when focusing on this. When succeded you proceed to do the foundation meditation while visualizing and helping yourself with that intent in mind. Do not be hard on yourself, nonlinear visualization and interruptions happen and are not a big deal. It matters to bring your focus back on the task and keep doing it until it becomes a habit and a learned ability.
Remember when first learning how to write, how hard it was to coordinate your hand? Similarly, spiritual disciplines manifest unto this learning curve. I bet you write very nice and fast today!