Each iPhone Tempered Glass comes with a complete cleaning kit. Before installing the screen protector, please follow the instructions for cleaning the screen. Use the alcohol wipe to remove dirt and fingerprints, clean your screen with the cleaning cloth and dust your screen with the included anti-dust stickers if necessary. Cleaning is extremely crucial to ensure proper application.
You have to make sure that all dirt and dust particles on the iPhone screen have been removed before installing the protective film. Even light dust or dirt can interfere with a bubble-free, problem-free application and possibly restrict the usability of the screen!