In the video, a person is seen using a small brush to apply a clear substance to their fingernail. The brush is carefully moved back and forth over the nail, ensuring that the substance is evenly distributed. The person's fingernail is already coated with a base layer of the substance, and the brush is being used to add a topcoat. The substance appears to be a clear polish, and the person is taking care to apply it evenly to avoid any streaks or bumps. The brush is small and precise, allowing for detailed work on the nail. The person's hand is steady, indicating that they are experienced in nail care. The video provides a close-up view of the process, allowing viewers to see the details of the application.