To use this harness, first adjust the nylon straps to fit your dog properly. Slip it over your dog's head and then secure it around the body. Make sure it's not too tight or too loose. When using, always hold the leash attached to the harness firmly for better control. As for maintenance, you can gently hand - wash it with mild soap and let it air - dry. Avoid using harsh chemicals or machine - washing, as this may damage the neoprene mesh material. Keep it in a cool, dry place when not in use.