Unscrew the cap of the Joyetech AIO and unscrew the coil unit. Screw the new coil into place onto the cap section. Prime coil before use by adding a few drops of e-liquid directly onto the coil and once replced allow to soak for 15 minutes before using. Do not overfill the AIO tank as fluid will be displaced when replacing the child-proof cap. Follow filling indicators.