Using the Phaser3D Dual ND Filter Holder for your GoPro Hero 5/6/7 is easy. First, select the ND4, ND8, ND16, or ND32 filters you need and place them into the holder. Then attach the holder to your GoPro camera. When shooting, you can control the amount of light entering the camera by adjusting the filters, which helps you get the right frame rate for smooth footage. As for maintenance, gently clean the holder with a soft cloth to keep it in good condition. Be careful not to drop or damage the holder, as it's made of TPU which can crack under heavy impact. Also, always store the holder in a safe place when not in use.