The video shows a person holding a cell phone with the back cover removed, revealing the battery. The person then applies a substance, likely a form of adhesive, to the battery with a tube. The substance is applied to the battery's surface, which is likely to help secure the battery in place or to prevent it from moving. The person's actions are deliberate and careful, ensuring that the substance is applied evenly across the battery's surface. The video provides a clear view of the process, allowing viewers to see the application of the substance in detail.