This video is a combination of the Durga Yantra (the mandala in the center of the video) with the Durga Mantra, providing a short but powerful meditation to invoke the energy of the goddess Durga. Durga is often shown riding on a lion, which gives you a hint of the qualities of Durga's presence. Lions can be loving and gentle creatures, but they can just as easily be fierce and deadly.
As the story goes, there was a demon named Mahishasura who could not be defeated by god or man, inflicting terror on the Earth. The gods united their powers to invoke Durga who, as a transcendent being, alone had the power to defeat Mahishasura. When we invoke Durga, it is usually to confront an inner demon that we have failed, time and time again, to overcome. Invoking Durga may not always be the most pleasant experience, as she brings her fire, but always benefecial. And so she helps us understand the difference between pleasant and beneficial :)
Enjoy, and make use of this video as your spirit is called to.