To remove, pull the head straight up. Place new brush head on top of zina45 sonic brush + press down. Place the brush head so that the center row of bristles is positioned between teeth and gums. Choose brushing mode. Begin brushing in circular motions in the upper right quadrant of mouth for 30 seconds. Every 30 seconds brush will briefly pause to alert user when to change quadrants in mouth (top right, top left, bottom right, bottom left). Brush will automatically stop after two minutes. After use, while brush is off, rinse brush head under warm running water. Stand toothbrush upright for hygienic drying and storage. Replace brush head every 3 months.